Computer-assisted tele-operated surgery systems and methods

ABSTRACT

Systems and methods for minimally invasive computer-assisted telesurgery are described. A computer-assisted teleoperated surgery system includes a teleoperated instrument actuation pod. The surgical instrument actuation pod includes a plurality of linear actuators arranged around a surgical instrument. The linear actuators engage with actuator engagement members on the instrument and so drive movable parts on the instrument. The actuation pod is mounted on a teleoperated manipulator. Instrument pod mass is close to the teleoperated manipulator to minimize the pod&#39;s inertia, momentum, and gravity effects on the manipulator.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a National Stage Application under 35 U.S.C. § 371and claims the benefit of International Application No.PCT/US2017/051846, filed Sep. 15, 2017, which claims the benefit ofpriority to U.S. Provisional Patent Application No. 62/395,025 (filedSep. 15, 2016), the disclosures of which are incorporated herein byreference.

COPYRIGHT NOTICE

A portion of the disclosure of this patent document contains materialwhich is subject to copyright protection. The copyright owner has noobjection to the facsimile reproduction by any-one of the patentdocument or the patent disclosure, as it appears in the Patent andTrademark Office patent file or records, but otherwise reserves allcopyright rights whatsoever.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

BACKGROUND

Teleoperated surgical systems (often called “robotic” surgical systemsbecause of the use of robot technology) and other computer-assisteddevices often include one or more instrument manipulators to manipulateinstruments for performing a task at a surgical work site and at leastone manipulator for supporting an image capturing device which capturesimages of the surgical work site. A manipulator arm comprises aplurality of links coupled together by one or more actively controlledjoints. In many embodiments, a plurality of actively controlled jointsmay be provided. The robot arm may also include one or more passivejoints, which are not actively controlled, but which comply withmovement of an actively controlled joint. Such active and passive jointsmay be various types, including revolute or prismatic joints. Thekinematic pose of the manipulator arm and its associated instrument orimage capture device may be determined by the positions of the jointsand knowledge of the structure and coupling of the links and theapplication of known kinematic calculations.

Minimally invasive telesurgical systems for use in surgery are beingdeveloped to increase a surgeon's dexterity as well as to allow asurgeon to operate on a patient from a remote location. Telesurgery is ageneral term for surgical systems in which the surgeon uses some form ofremote control, e.g., a servomechanism, or the like, to manipulatesurgical instrument movements rather than directly holding and movingthe instruments by hand. In such a telesurgery system, the surgeon isprovided with an image of the surgical site at the remote location.While viewing typically a stereoscopic image of the surgical site thatprovides the illusion of depth on a suitable viewer or display, thesurgeon performs the surgical procedures on the patient by manipulatingmaster control input devices, which in turn control the motion ofcorresponding teleoperated instruments. The teleoperated surgicalinstruments can be inserted through small, minimally invasive surgicalapertures or natural orifices to treat tissues at surgical sites withinthe patient, often avoiding the trauma generally associated withaccessing a surgical worksite by open surgery techniques. Thesecomputer-assisted tele-operated systems can move the working ends (endeffectors) of the surgical instruments with sufficient dexterity toperform quite intricate surgical tasks, often by pivoting shafts of theinstruments at the minimally invasive aperture, sliding of the shaftaxially through the aperture, rotating of the shaft within the aperture,and the like.

SUMMARY

The following summary introduces certain aspects of the inventivesubject matter in order to provide a basic understanding. This summaryis not an extensive overview of the inventive subject matter, and it isnot intended to identify key or critical elements or to delineate thescope of the inventive subject matter. Although this summary containsinformation that is relevant to various aspects and embodiments of theinventive subject matter, its sole purpose is to present some aspectsand embodiments in a general form as a prelude to the more detaileddescription below.

In one aspect, a telesurgical system includes an actuation pod and aninstrument mounted in the actuation pod. The actuation pod has alongitudinal axis, and the instrument's shaft is coincident with thepod's longitudinal axis. The pod has linear actuators (e.g., motors,lead screws, and a nut threaded on each lead screw). The linearactuators each engage actuator input members on the instrument. Infurther aspects, the pod components are arranged to place the pod'scenter of mass on the pod's longitudinal axis and distally toward thepatient so that the effects of inertia, momentum, and gravity on the podare minimized as a manipulator orients the pod's longitudinal axis inpitch and yaw.

More generally, this disclosure provides devices and methods forminimally invasive robotic surgery using a computer-assistedtele-operated surgery device. For example, this disclosure providessurgical instrument actuation pods for a computer-assisted tele-operatedsurgery system. In some embodiments, the surgical instrument actuationpods include a plurality of threaded nuts that are concurrentlypositionable at a common position along the longitudinal axis of thepod. Some embodiments include a plurality of anti-rotation shafts, andeach anti-rotation shaft is slidably coupled with two and no more thantwo of the threaded nuts.

In one aspect, the disclosure is directed to a surgical instrumentactuation pod for a computer-assisted tele-operated surgery system. Sucha surgical instrument actuation pod includes: a plurality of motors; aplurality of lead screws, each lead screw rotatably driven by arespective one of the motors; and a plurality of threaded nuts, eachthreaded nut threadably coupled with a respective one of the lead screwsand releasably attachable to a respective actuator engagement member ofa surgical instrument. The pod defines a longitudinal axis. All of thethreaded nuts are concurrently positionable at a common position alongthe longitudinal axis.

Such a surgical instrument actuation pod may optionally include one ormore of the following features. The surgical instrument actuation podmay also include a frame comprising: a distal end plate; a proximal endplate; and a plurality of anti-rotation shafts extending between theproximal end plate and the distal end plate. Each of the lead screws maybe rotatably coupled to the distal end plate and the proximal end plate.The distal end plate may comprise a fully-circumferential ring platedefining an open center for receiving a shaft of the surgicalinstrument. The proximal end plate may comprise a C-shaped plate. Eachof the motors may be mounted to the distal end plate while no motors aremounted to the proximal end plate. Each of the anti-rotation shafts maybe slidably coupled with no more than two of the threaded nuts. Adjacentpairs of the threaded nuts may be slidably coupled with a respective oneof the anti-rotation shafts. All of the motors may be arrangedconcentrically around the longitudinal axis.

In another aspect, this disclosure is directed to a surgical instrumentactuation pod for a computer-assisted tele-operated surgery system. Sucha surgical instrument actuation pod includes: a plurality of motors; aplurality of lead screws, each of the lead screws rotatably driven by arespective one of the motors; a plurality of threaded nuts, eachthreaded nut threadably coupled with a respective one of the lead screwsand releasably attachable with a respective actuator engagement memberof a surgical instrument; and a plurality of anti-rotation shafts. Eachanti-rotation shaft is slidably coupled with two and no more than two ofthe threaded nuts.

Such a surgical instrument actuation pod may optionally include one ormore of the following features. The pod defines a longitudinal axis, andeach of the threaded nuts may be concurrently positioned at a commonposition along the longitudinal axis. The pod may also include a distalend plate and a proximal end plate. The plurality of anti-rotationshafts may extend between the proximal end plate and the distal endplate. The distal end plate may comprise a fully-circumferential ringplate defining an open center for receiving a shaft of the surgicalinstrument. The proximal end plate may comprise a C-shaped plate. Eachof the motors may be mounted to the distal end plate while no motors aremounted to the proximal end plate. The plurality of motors may bearranged concentrically around the longitudinal axis. Each of thethreaded nuts may be slidably coupled with only one of the anti-rotationshafts.

In another aspect, this disclosure is directed to a surgical instrumentand surgical instrument actuation pod system for a computer-assistedtele-operated surgery system. The surgical instrument and surgicalinstrument actuation pod system includes the surgical instrument and thesurgical instrument actuation pod. The surgical instrument includes: aproximal end portion; an instrument shaft extending from the proximalend portion, the instrument shaft including a distal end portionopposite from the proximal end portion; an end effector coupled to thedistal end portion, the end effector movable relative to the instrumentshaft; and a plurality of actuator engagement members movably coupledwith the proximal end portion. The pod includes: a distal end platecomprising a fully-circumferential ring plate defining an open centerfor receiving the instrument shaft; a proximal end plate comprising aC-shaped plate; a plurality of anti-rotation shafts extending betweenthe proximal end plate and the distal end plate; a plurality of motorsmounted to the distal end plate; a plurality of lead screws, each of thelead screws rotatably driven by a respective one of the motors; and aplurality of threaded nuts. Each of the threaded nuts is threadablycoupled with a respective one of the lead screws and releasablyattachable with a respective one of the actuator engagement members.

Such a surgical instrument and surgical instrument actuation pod systemmay optionally include one or more of the following features. Theplurality of actuator engagement members may include a first actuatorengagement member coupled to a first tensioning member extending alongthe instrument shaft and a second actuator engagement member coupled toa second tensioning member extending along the instrument shaft. Thefirst and second tensioning members may each be coupled to the endeffector such that moving the first actuator engagement memberproximally moves the second actuator engagement member distally andmoves the end effector in a first manner relative to the instrumentshaft. Moving the second actuator engagement member proximally may movethe first actuator engagement member distally and move the end effectorin a second manner relative to the instrument shaft (the second manneropposing the first manner). The pod defines a longitudinal axis, andwhile the surgical instrument is coupled with the pod, each of thethreaded nuts may be concurrently positionable at a common positionalong the longitudinal axis. Each of the anti-rotation shafts may beslidably coupled with two and no more than two of the threaded nuts.Each of the threaded nuts may be slidably coupled with a single one ofthe anti-rotation shafts. The pod defines a longitudinal axis, and theplurality of motors may be arranged concentrically around thelongitudinal axis. The proximal end portion of the surgical instrumentmay include a handle configured to facilitate manual gripping andmanipulation of the surgical instrument. While the surgical instrumentis coupled with the pod, the handle may extend farther radially thanadjacent portions of the pod.

Some or all of the embodiments described herein may provide one or moreof the following advantages. In some cases, the tele-operated surgicalinstrument actuation pods provided herein are advantageously structuredto negate the effects of surgical instrument cable stretch. Cableswithin conventional tele-operated surgical instruments are pre-tensionedduring manufacturing, but the tensions may tend to decrease over timebecause the cables may stretch as the instruments are used. Such tensiondecreases can contribute to a lessening in the accuracy of control ofthe tele-operated surgical instruments in some cases. Additionally,autoclave sterilization of the tele-operated surgical instruments usingheat and humidity can exacerbate cable stretch and losses of cabletension. The tele-operated surgical instrument actuation pods providedherein advantageously compensate for surgical instrument cable stretchwithout a loss in the accuracy of control of the instruments.

In addition, the tele-operated surgical instrument actuation podsprovided herein are advantageously structured to be compact and to havea relatively low mass and inertia. In addition, the mass distribution issubstantially constant such that the inertia is substantially constant,and therefore predictable.

Still further, in some embodiments the tele-operated surgical instrumentactuation pods provided herein are advantageously structured tointerface with a surgical instrument in a manner that is readilydetachable. For example, in some embodiments the surgical instrument canbe detached from an instrument drive system merely by actuating a latchmechanism and retracting the instrument proximally out of engagementwith the drive system. Such a readily detachable interface between thesurgical instrument and the instrument drive system can provideadvantages such as quick instrument removal in the event of anemergency, and user convenience during general change-outs of onesurgical instrument for another.

The details of one or more embodiments are set forth in the accompanyingdrawings and the description below. Other features, objects, andadvantages will be apparent from the description and drawings, and fromthe claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an example patient-side unit of acomputer-assisted tele-operated surgery system.

FIG. 2 is a front view of an example surgeon control unit of acomputer-assisted tele-operated surgery system.

FIG. 3 is a side view of an example manipulator arm assembly of acomputer-assisted tele-operated surgery system.

FIG. 4 is a perspective view of another type of patient-sidecomputer-assisted tele-operated surgery system.

FIG. 5 is a perspective view of a distal end portion of an examplesurgical instrument in a first pose.

FIG. 6 is a perspective view of the distal end portion of the surgicalinstrument of FIG. 5 in a second pose.

FIG. 7 is a perspective view of the distal end portion of the surgicalinstrument of FIG. 5 in a third pose.

FIG. 8 is a simplified schematic diagram of an example tele-operatedsurgical instrument in accordance with some embodiments.

FIG. 9 is a schematic diagram of the tele-operated surgical instrumentof FIG. 8 coupled with an example instrument drive system in accordancewith some embodiments.

FIG. 10 is a force diagram pertaining to the instrument and drive systemof FIG. 9.

FIG. 11 is a schematic diagram of the instrument and drive system ofFIG. 9 with the end effector oriented in an example pose.

FIG. 12 is a schematic diagram of the instrument and drive system ofFIG. 11 with the instrument extended distally in relation to the drivesystem while the end effector remains oriented in the example pose.

FIG. 13 is a schematic diagram of the instrument and drive system ofFIG. 11 with the instrument retracted proximally in relation to thedrive system while the end effector remains oriented in the examplepose.

FIG. 14 is a schematic diagram of a portion of the instrument and drivesystem of FIG. 11 showing example locations of force sensors fordetecting forces such as cable tension.

FIG. 15 is a perspective view of an example surgical instrument that isconfigured in accordance with the schematic diagram of FIG. 9.

FIG. 16 is a perspective view of a proximal end portion of the surgicalinstrument of FIG. 15.

FIG. 17 is another perspective view of the surgical instrument of FIG.15.

FIG. 18 is a proximal end view of the surgical instrument of FIG. 15.

FIG. 19 depicts how the surgical instrument of FIG. 15 can be coupledwith an example instrument drive system in accordance with someembodiments.

FIG. 20 is a perspective view a surgical instrument actuation pod.

FIGS. 21-25 are perspective views of a surgical instrument actuation podwith its covering housing removed.

FIG. 26 is a cross-sectional view of a surgical instrument mounted in anactuation pod.

FIGS. 27-29 are perspective views of a surgical instrument mounted in anactuation pod and positioned at various insertion depths.

DETAILED DESCRIPTION

This description and the accompanying drawings that illustrate inventiveaspects, embodiments, implementations, or applications should not betaken as limiting—the claims define the protected invention. Variousmechanical, compositional, structural, electrical, and operationalchanges may be made without departing from the spirit and scope of thisdescription and the claims. In some instances, well-known circuits,structures, or techniques have not been shown or described in detail inorder not to obscure the invention. Like numbers in two or more figuresrepresent the same or similar elements.

Further, specific words chosen to describe one or more embodiments andoptional elements or features are not intended to limit the invention.For example, spatially relative terms—such as “beneath”, “below”,“lower”, “above”, “upper”, “proximal”, “distal”, and the like—may beused to describe one element's or feature's relationship to anotherelement or feature as illustrated in the figures. These spatiallyrelative terms are intended to encompass different locations (i.e.,translational placements) and orientations (i.e., rotational placements)of a device in use or operation in addition to the location andorientation shown in the figures. For example, if a device in thefigures is turned over, elements described as “below” or “beneath” otherelements or features would then be “above” or “over” the other elementsor features. Thus, the exemplary term “below” can encompass bothlocations and orientations of above and below. A device may be otherwiseoriented (e.g., rotated 90 degrees or at other orientations) and thespatially relative descriptors used herein interpreted accordingly.Likewise, descriptions of movement along (translation) and around(rotation) various axes includes various special device locations andorientations. The combination of a body's location and orientationdefine the body's pose.

Similarly, geometric terms, such as “parallel”, “perpendicular”,“round”, or “square”, are not intended to require absolute mathematicalprecision, unless the context indicates otherwise. Instead, suchgeometric terms allow for variations due to manufacturing or equivalentfunctions. For example, if an element is described as “round” or“generally round”, a component that is not precisely circular (e.g., onethat is slightly oblong or is a many-sided polygon) is still encompassedby this description. The words “including” or “having” mean includingbut not limited to.

It should be understood that although this description is made to besufficiently clear, concise, and exact, scrupulous and exhaustivelinguistic precision is not always possible or desirable, since thedescription should be kept to a reasonable length and skilled readerswill understand background and associated technology. For example,considering a video signal, a skilled reader will understand that anoscilloscope described as displaying the signal does not display thesignal itself but a representation of the signal, and that a videomonitor described as displaying the signal does not display the signalitself but video information the signal carries.

In addition, the singular forms “a”, “an”, and “the” are intended toinclude the plural forms as well, unless the context indicatesotherwise. And, the terms “comprises”, “includes”, “has”, and the likespecify the presence of stated features, steps, operations, elements,and/or components but do not preclude the presence or addition of one ormore other features, steps, operations, elements, components, and/orgroups. And, each of the one or more individual listed items should beconsidered optional unless otherwise stated, so that variouscombinations of items are described without an exhaustive list of eachpossible combination. The auxiliary verb may likewise implies that afeature, step, operation, element, or component is optional.

Elements described in detail with reference to one embodiment,implementation, or application optionally may be included, wheneverpractical, in other embodiments, implementations, or applications inwhich they are not specifically shown or described. For example, if anelement is described in detail with reference to one embodiment and isnot described with reference to a second embodiment, the element maynevertheless be claimed as included in the second embodiment. Thus, toavoid unnecessary repetition in the following description, one or moreelements shown and described in association with one embodiment,implementation, or application may be incorporated into otherembodiments, implementations, or aspects unless specifically describedotherwise, unless the one or more elements would make an embodiment orimplementation non-functional, or unless two or more of the elementsprovide conflicting functions.

Elements described as coupled may be electrically or mechanicallydirectly coupled, or they may be indirectly coupled via one or moreintermediate components.

The term “flexible” in association with a part, such as a mechanicalstructure, component, or component assembly, should be broadlyconstrued. In essence, the term means the part can be repeatedly bentand restored to an original shape without harm to the part. Many “rigid”objects have a slight inherent resilient “bendiness” due to materialproperties, although such objects are not considered “flexible” as theterm is used herein. A flexible part may have infinite degrees offreedom (DOF's). Examples of such parts include closed, bendable tubes(made from, e.g., NITINOL, polymer, soft rubber, and the like), helicalcoil springs, etc. that can be bent into various simple or compoundcurves, often without significant cross-sectional deformation. Otherflexible parts may approximate such an infinite-DOF part by using aseries of closely spaced components that are similar to a snake-likearrangement of serial “vertebrae.” In such a vertebral arrangement, eachcomponent is a short link in a kinematic chain, and movable mechanicalconstraints (e.g., pin hinge, cup and ball, live hinge, and the like)between each link may allow one (e.g., pitch) or two (e.g., pitch andyaw) DOF's of relative movement between the links. A short, flexiblepart may serve as, and be modeled as, a single mechanical constraint(joint) that provides one or more DOF's between two links in a kinematicchain, even though the flexible part itself may be a kinematic chainmade of several coupled links. Knowledgeable persons will understandthat a part's flexibility may be expressed in terms of its stiffness.

Unless otherwise stated in this description, a flexible part, such as amechanical structure, component, or component assembly, may be eitheractively or passively flexible. An actively flexible part may be bent byusing forces inherently associated with the part itself. For example,one or more tendons may be routed lengthwise along the part and offsetfrom the part's longitudinal axis, so that tension on the one or moretendons causes the part or a portion of the part to bend. Other ways ofactively bending an actively flexible part include, without limitation,the use of pneumatic or hydraulic power, gears, electroactive polymer(more generally, “artificial muscle”), and the like. A passivelyflexible part is bent by using a force external to the part (e.g., anapplied mechanical or electromagnetic force). A passively flexible partmay remain in its bent shape until bent again, or it may have aninherent characteristic that tends to restore the part to an originalshape. An example of a passively flexible part with inherent stiffnessis a plastic rod or a resilient rubber tube. An actively flexible part,when not actuated by its inherently associated forces, may be passivelyflexible. A single part may be made of one or more actively andpassively flexible parts in series.

An example of a teleoperated surgical system is the da Vinci® SurgicalSystem, commercialized by Intuitive Surgical, Inc. of Sunnyvale, Calif.Inventive aspects are associated with computer-assisted teleoperatedsurgical systems. Knowledgeable persons will understand that inventiveaspects disclosed herein may be embodied and implemented in variousways, including computer-assisted and hybrid combinations of manual andcomputer-assisted embodiments and implementations. As applicable,inventive aspects may be embodied and implemented in both relativelysmaller, hand-held, hand-operated devices and relatively larger systemsthat have additional mechanical support, as well as in other embodimentsof computer-assisted tele-operated medical devices. In addition,inventive aspects are associated with advances in computer-assistedsurgical systems that include autonomous rather than teleoperatedactions, and so both teleoperated and autonomous surgical systems areincluded, even though the description concentrates on teleoperatedsystems.

A computer is a machine that follows programmed instructions to performmathematical or logical functions on input information to produceprocessed output information. A computer includes a logic unit thatperforms the mathematical or logical functions, and memory that storesthe programmed instructions, the input information, and the outputinformation. The term “computer” and similar terms, such as “processor”or “controller”, encompasses both centralized single-location anddistributed implementations.

This disclosure provides improved surgical and telesurgical devices,systems, and methods. The inventive concepts are particularlyadvantageous for use with telesurgical systems in which a plurality ofsurgical tools or instruments are mounted on and moved by an associatedplurality of teleoperated manipulators during a surgical procedure. Theteleoperated surgical systems will often comprise tele-robotic,telesurgical, and/or telepresence systems that include processorsconfigured as master-slave controllers. By providing teleoperatedsurgical systems employing processors appropriately configured to movemanipulator assemblies with articulated linkages having relatively largenumbers of degrees of freedom, the motion of the linkages can betailored for work through a minimally invasive access site. The largenumber of degrees of freedom may also allow a processor to position themanipulators to inhibit interference or collisions between these movingstructures, and the like.

The manipulator assemblies described herein will often include ateleoperated manipulator and a tool mounted thereon (the tool oftencomprising a surgical instrument in surgical versions), although theterm “manipulator assembly” will also encompass the manipulator withoutthe tool mounted thereon. The term “tool” encompasses both general orindustrial robotic tools and specialized robotic surgical instruments,with these later structures often including an end effector that issuitable for manipulation of tissue, treatment of tissue, imaging oftissue, or the like. The tool/manipulator interface will often be aquick disconnect tool holder or coupling, allowing rapid removal andreplacement of the tool with an alternate tool. The manipulator assemblywill often have a base that is fixed in space during at least a portionof a telesurgical procedure, and the manipulator assembly may include anumber of degrees of freedom between the base and an end effector of thetool. Actuation of the end effector (such as opening or closing of thejaws of a gripping device, energizing an electrosurgical paddle, or thelike) will often be separate from, and in addition to, these manipulatorassembly degrees of freedom.

The end effector will typically move in the workspace with between twoand six degrees of freedom. As used herein, the term “position”encompasses both location and orientation. Hence, a change in a positionof an end effector (for example) may involve a translation of the endeffector from a first location to a second location, a rotation of theend effector from a first orientation to a second orientation, or acombination of both. As used herein, the term “end effector” thereforeincludes but is not limited to the function of changing the orientationor position (e.g., a “wrist” function, a parallel motion function) ofits distal-most part or parts (e.g., jaw(s) and the like).

When used for minimally invasive teleoperated surgery, movement of themanipulator assembly may be controlled by a processor of the system sothat a shaft or intermediate portion of the tool or instrument isconstrained to a safe motion through a minimally invasive surgicalaccess site or other aperture. Such motion may include, for example,axial insertion of the shaft through the aperture site, rotation of theshaft about its axis, and pivotal motion of the shaft about a pivotpoint adjacent the access site, but will often preclude excessivelateral motion of the shaft which might otherwise tear the tissuesadjacent the aperture or enlarge the access site inadvertently. Some orall of such constraint on the manipulator motion at the access site maybe imposed using mechanical manipulator joint linkages that inhibitimproper motions, or may in part or in full be imposed using roboticdata processing and control techniques. Hence, such minimally invasiveaperture-constrained motion of the manipulator assembly may employbetween zero and three degrees of freedom of the manipulator assembly.

Many of the exemplary manipulator assemblies described herein will havemore degrees of freedom than are needed to position and move an endeffector within a surgical site. For example, a surgical end effectorthat can be positioned with six degrees of freedom at an internalsurgical site through a minimally invasive aperture may in someembodiments have nine degrees of freedom (six end effector degrees offreedom-three for location, and three for orientation-plus three degreesof freedom to comply with the access site constraints), but will oftenhave ten or more degrees of freedom. Highly configurable manipulatorassemblies having more degrees of freedom than are needed for a givenend effector position can be described as having or providing sufficientdegrees of freedom to allow a range of joint states for an end effectorposition in a workspace. For example, for a given end effector position,the manipulator assembly may occupy (and be driven between) any of arange of alternative manipulator linkage positions. Similarly, for agiven end effector velocity vector, the manipulator assembly may have arange of differing joint movement speeds for the various joints of themanipulator assembly.

Referring to FIGS. 1 and 2, systems for minimally invasivecomputer-assisted telesurgery (as referred to herein as “minimallyinvasive robotic surgery”) can include a patient-side unit 100 and asurgeon control unit 40. Telesurgery is a general term for surgicalsystems where the surgeon uses some form of remote control, e.g., aservomechanism, or the like, to manipulate surgical instrument movementsby using robot technology rather than directly holding and moving theinstruments by hand. The robotically manipulatable surgical instrumentscan be inserted through small, minimally invasive surgical apertures totreat tissues at surgical sites within the patient, avoiding the traumaassociated with accessing for open surgery. These robotic systems canmove the working ends of the surgical instruments with sufficientdexterity to perform quite intricate surgical tasks, often by pivotingshafts of the instruments at the minimally invasive aperture, sliding ofthe shaft axially through the aperture, rotating of the shaft within theaperture, and/or the like.

In the depicted embodiment, the patient-side unit 100 includes a base110, a first robotic manipulator arm assembly 120, a second roboticmanipulator arm assembly 130, a third robotic manipulator arm assembly140, and a fourth robotic manipulator arm assembly 150. As shown, thebase 110 includes a portion that rests on the floor, a vertical column,and a horizontal boom, and other base configurations to mechanicallyground the patient-side unit may optionally be used. Each roboticmanipulator arm assembly 120, 130, 140, and 150 is pivotably coupled tothe base 110. In some embodiments, fewer than four or more than fourrobotic manipulator arm assemblies may be included as part of thepatient-side unit 100. While in the depicted embodiment the base 110includes casters to allow ease of mobility, in some embodiments thepatient-side unit 100 is fixedly mounted to a floor, ceiling, operatingtable, structural framework, or the like.

In a typical application, two of the robotic manipulator arm assemblies120, 130, 140, or 150 hold surgical instruments and a third holds astereo endoscope. The remaining robotic manipulator arm assembly isavailable so that another instrument may be introduced at the work site.Alternatively, the remaining robotic manipulator arm assembly may beused for introducing a second endoscope or another image capturingdevice, such as an ultrasound transducer, to the work site.

Each of the robotic manipulator arm assemblies 120, 130, 140, and 150 isconventionally formed of links that are coupled together and manipulatedthrough actuatable joints. Each of the robotic manipulator armassemblies 120, 130, 140, and 150 includes a setup arm and a devicemanipulator. The setup arm positions its held device so that a pivotpoint occurs at its entry aperture into the patient. The devicemanipulator may then manipulate its held device (tool; surgicalinstrument) so that it may be pivoted about the pivot point, insertedinto and retracted out of the entry aperture, and rotated about itsshaft axis.

In the depicted embodiment, the surgeon console 40 includes a stereovision display 45 so that the user may view the surgical work site instereo vision from images captured by the stereoscopic camera of thepatient-side cart 100. Left and right eyepieces 46 and 47 are providedin the stereo vision display 45 so that the user may view left and rightdisplay screens inside the display 45 respectively with the user's leftand right eyes. While viewing typically an image of the surgical site ona suitable viewer or display, the surgeon performs the surgicalprocedures on the patient by manipulating master control input devices,which in turn control the motion of robotic instruments.

The surgeon console 40 also includes left and right input devices 41, 42that the user may grasp respectively with his/her left and right handsto manipulate devices (e.g., surgical instruments) being held by therobotic manipulator arm assemblies 120, 130, 140, and 150 of thepatient-side cart 100 in preferably six degrees-of-freedom (“DOF”). Footpedals 44 with toe and heel controls are provided on the surgeon console40 so the user may control movement and/or actuation of devicesassociated with the foot pedals. Additional input to the system may bemade via one or more other inputs, such as buttons, touch pads, voice,and the like, as illustrated by input 49.

A processor 43 is provided in the surgeon console 40 for control andother purposes. The processor 43 performs various functions in themedical robotic system. One function performed by processor 43 is totranslate and transfer the mechanical motion of input devices 41, 42 toactuate their respective joints in their associated robotic manipulatorarm assemblies 120, 130, 140, and 150 so that the surgeon caneffectively manipulate devices, such as the surgical instruments.Another function of the processor 43 is to implement the methods,cross-coupling control logic, and controllers described herein.

Although described as a processor, it is to be appreciated that theprocessor 43 may be implemented by any combination of hardware,software, and firmware. Also, its functions as described herein may beperformed by one unit or divided up among a number of subunits, each ofwhich may be implemented in turn by any combination of hardware,software, and firmware. Further, although being shown as part of orbeing physically adjacent to the surgeon control unit 40, the processor43 may also be distributed as subunits throughout the telesurgerysystem. Accordingly, control aspects referred to herein are implementedvia processor 43 in either a centralized or distributed form.

Referring also to FIG. 3, the robotic manipulator arm assemblies 120,130, 140, and 150 can manipulate devices such as surgical instruments toperform minimally invasive surgery. For example, in the depictedarrangement the robotic manipulator arm assembly 120 is pivotablycoupled to an instrument holder 122. A cannula 180 and a surgicalinstrument 200 and are, in turn, releasably coupled to the instrumentholder 122. The cannula 180 is a tubular member that is located at thepatient interface site during a surgery. The cannula 180 defines a lumenin which an elongate shaft 220 of the surgical instrument 200 isslidably disposed. As described further below, in some embodiments thecannula 180 includes a distal end portion with a body wall retractormember.

The instrument holder 122 is pivotably coupled to a distal end of therobotic manipulator arm assembly 120. In some embodiments, the pivotablecoupling between the instrument holder 122 and the distal end of roboticmanipulator arm assembly 120 is a motorized joint that is actuatablefrom the surgeon console 40 and processor 43.

The instrument holder 122 includes an instrument holder frame 124, acannula clamp 126, and an instrument holder carriage 128. In thedepicted embodiment, the cannula clamp 126 is fixed to a distal end ofthe instrument holder frame 124. The cannula clamp 126 can be actuatedto couple with, or to uncouple from, the cannula 180. The instrumentholder carriage 128 is movably coupled to the instrument holder frame124. More particularly, the instrument holder carriage 128 is linearlytranslatable along the instrument holder frame 124. In some embodiments,the movement of the instrument holder carriage 128 along the instrumentholder frame 124 is a motorized, translational movement that isactuatable/controllable by the processor 43.

The surgical instrument 200 includes a transmission assembly 210, theelongate shaft 220, and an end effector 230. The transmission assembly210 is releasably coupleable with the instrument holder carriage 128.The shaft 220 extends distally from the transmission assembly 210. Theend effector 230 is disposed at a distal end of the shaft 220.

The shaft 220 defines a longitudinal axis 222 that is coincident with alongitudinal axis of the cannula 180. As the instrument holder carriage128 translates along the instrument holder frame 124, the elongate shaft220 of the surgical instrument 200 is moved along the longitudinal axis222. In such a manner, the end effector 230 can be inserted and/orretracted from a surgical workspace within the body of a patient.

Also referring to FIG. 4, another example patient-side system 160 forminimally invasive computer-assisted tele-operated surgery includes afirst robotic manipulator arm assembly 162 and a second roboticmanipulator arm assembly 164 that are each mounted to an operating table10. In some cases, this configuration of patient-side system 160 can beused as an alternative to the patient-side unit 100 of FIG. 1. Whileonly two robotic manipulator arm assemblies 162 and 164 are depicted, itshould be understood that more than two (e.g., three, four, five, six,and more than six) can be included in some configurations.

In some cases, the operating table 10 may be moved or reconfiguredduring the surgery. For example, in some cases, the operating table 10may be tilted about various axes, raised, lowered, pivoted, rotated, andthe like. In some cases, by manipulating the orientation of theoperating table 10, the clinicians can utilize the effects of gravity toposition internal organs of the patient in positions that facilitateenhanced surgical access. In some cases, such movements of the operatingtable 10 may be integrated as a part of the computer-assistedtele-operated surgery system, and controlled by the system.

Also referring to FIGS. 5-7, a variety of alternative computer-assistedtele-operated surgical instruments of different types and differing endeffectors 230 may be used, with the instruments of at least some of themanipulators being removed and replaced during a surgical procedure.Several of these end effectors, including, for example, DeBakey Forceps56 i, microforceps 56 ii, and Potts scissors 56 iii include first andsecond end effector elements 56 a, 56 b which pivot relative to eachother so as to define a pair of end effector jaws. Other end effectors,including scalpels and electrocautery probes, have a single end effectorelement. For instruments having end effector jaws, the jaws will oftenbe actuated by squeezing the grip members of input devices 41, 42.

In some cases, the computer-assisted tele-operated surgical instrumentsinclude multiple degrees of freedom such as, but not limited to, roll,pitch, yaw, insertion depth, opening/closing of jaws, actuation ofstaple delivery, activation of electro-cautery, and the like. At leastsome of such degrees of freedom can be actuated by an instrument drivesystem to which the surgical instrument can be selectively coupled.

In some embodiments, the computer-assisted tele-operated surgicalinstruments include end effectors with two individually movablecomponents such as, but not limited to, opposing jaws designed forgrasping or shearing. When a first one of the individually movablecomponents is moved as a second one of the individually movablecomponents remains generally stationary or is moved in an opposingmanner, the end effector can perform useful motions such as opening andclosing for grasping, shearing, releasing, and the like. When the twocomponents are moved synchronously in the same direction, speed anddistance, the resulting motion is a type of pitch or yaw movement of theend effector. Hence, in some surgical instrument embodiments that haveend effectors with two individually movable components, such as jaws,the arrangement can provide two degrees of freedom (e.g., pitch/yawmovements and opening/closing movements).

The elongate shaft 220 allow the end effector 230 and the distal end ofthe shaft 220 to be inserted distally into a surgical worksite through aminimally invasive aperture (via cannula 180), often through a body wall(e.g., abdominal wall) or the like. In some cases, a body wall retractormember on a distal end of the cannula 180 can be used to tent the bodywall, thereby increasing the surgical workspace size. In some cases thesurgical worksite may be insufflated, and movement of the end effectors230 within the patient will often be effected, at least in part, bypivoting of the instruments 200 about the location at which the shaft220 passes through the minimally invasive aperture. In other words, therobotic manipulator arm assemblies 120, 130, 140, and 150 will move thetransmission assembly 210 outside the patient so that the shaft 220extends through a minimally invasive aperture location so as to helpprovide a desired movement of end effector 50. Hence, the roboticmanipulator arm assemblies 120, 130, 140, and 150 will often undergosignificant movement outside patient during a surgical procedure.

Referring to FIG. 8, an example surgical instrument 300 that can be usedas part of a computer-assisted tele-operated surgery system isschematically depicted. The surgical instrument 300 includes aninstrument shaft 302 (similar to shafts 220, 640) having a proximal(away from the surgical site) end portion 310 and a distal (toward thesurgical site) end portion 320 opposite from the proximal end portion310. The surgical instrument 300 also includes an end effector 330(similar to end effectors 230, 650). In this schematic diagram, the endeffector 330 is depicted as having a single degree of freedom inrelation to the instrument shaft 302 (i.e., a freedom to yaw the endeffector 330 in a rotary or pivoting fashion). It should be understood,however, that the end effectors 330 of the surgical instrumentsdescribed herein can have more than one degree of freedom (e.g., two,three, four, five, six, or more than six degrees of freedom). Moreover,it should be understood that the concepts described in the context ofthe single degree of freedom of the end effector 330 can be extended toeach degree of freedom of multiple degrees of freedom of the surgicalinstrument 300 and of other types of surgical instruments forcomputer-assisted tele-operated surgery systems.

Example surgical instrument 300 also includes a first tensioning member340, a first actuator engagement member 350, a second tensioning member360, and a second actuator engagement member 370. The first tensioningmember 340 is coupled to the end effector 330 and extends along theinstrument shaft 302 where it terminates at the first actuatorengagement member 350. Similarly, the second tensioning member 360 iscoupled to the end effector 330 and extends along the instrument shaft302 where it terminates at the second actuator engagement member 370.The first actuator engagement member 350 and the second actuatorengagement member 370 are movably coupled to the proximal end portion310 of the surgical instrument. In some embodiments, the first actuatorengagement member 350 and the second actuator engagement member 370 areslidably coupled to the proximal end portion 310 of the surgicalinstrument.

While the depicted embodiment includes sliding actuator engagementmembers 350 and 370, in some embodiments one or more other types ofactuator engagement members can be included in the surgical instrument300. For example, in some embodiments rotatable actuator engagementmembers are included. Such rotatable actuator engagement members can becoupled to capstans or pulleys that are engaged with the tensioningmembers 340 and 360. Rotation of the rotatable actuator engagementmembers can apply or relieve tension on the corresponding tensioningmember 340 and 360. Accordingly, movements of the end effector 330 andtensioning of the tensioning member 340 and 360 can be controlled viarotatable actuator engagement members.

In some embodiments, some or all portions of the first tensioning member340 and the second tensioning member 360 comprise flexible cables (e.g.,without limitation, stranded tungsten cables, stainless steel cables,etc.). In some embodiments, the first tensioning member 340 and thesecond tensioning member 360 are different portions of a singlecontinuous cable. In some embodiments, the first tensioning member 340and the second tensioning member 360 are separate cables. The firsttensioning member 340 and the second tensioning member 360 mayadditionally or alternatively include other components such as, but notlimited to, hypo-tubes.

The first tensioning member 340 and the second tensioning member 360 areeach coupled to the end effector 330. In the depicted embodiment, thefirst tensioning member 340 and the second tensioning member 360 areeach coupled to the end effector 330 via a pulley 332 (which can be acapstan, crank arm, rotary drive member, etc.). Hence, a proximalmovement of the first actuator engagement member 350 moves the secondactuator engagement member 370 distally, and moves the end effector 330in a first manner relative to the instrument shaft 302. Conversely, aproximal movement of the second actuator engagement member 370 moves thefirst actuator engagement member 350 distally, and moves the endeffector 330 in a second manner relative to the instrument shaft 302. Inthis fashion, desired movements of the end effector 330 can befacilitated in a controlled manner. Moreover, as described furtherbelow, while the movements and/or pose of the end effector 330 is beingcontrolled using actuator engagement members 350 and 370, the tensionsin the tensioning members 340 and 360 can be concurrently controlled. Ineffect, two degrees of freedom (e.g., end effector 330 position andtensioning members 340 and 360 tension) of the surgical instrument 300can be concurrently controlled in accordance with the devices andmethods described herein.

The surgical instrument 300 is depicted here as being separated from aninstrument drive system. Accordingly, in some embodiments the tension inthe first tensioning member 340 and the second tensioning member 360 canbe less than the tension used during the operation of the surgicalinstrument 300. In some cases, having a relatively low tension in thefirst tensioning member 340 and the second tensioning member 360 whilethe surgical instrument 300 is not in use can be advantageous (e.g., toreduce the potential for cable stretch). In some embodiments, pre-loadtensioning members (e.g., springs, not shown) may be included insurgical instrument 300 to maintain a minimal tension in the firsttensioning member 340 and the second tensioning member 360 while thesurgical instrument 300 is separated from an instrument drive system.Such minimal pre-tensioning may help ensure that the first tensioningmember 340 and the second tensioning member 360 remain oriented withinthe surgical instrument 300 as desired.

While the surgical instrument 300 is depicted as having a single degreeof freedom, it should be understood that this is a simplified schematicdiagram and that the surgical instrument 300 can have two or moredegrees of freedom. The concepts described herein in reference to thesingle degree of freedom of surgical instrument 300 (as depicted) can beextrapolated to the two or more degrees of freedom of the surgicalinstruments provided herein. For example, when the end effector 330includes two individually movable components, such as opposing jawsdesigned for grasping or shearing as described above, the arrangementprovides two degrees of freedom (e.g., pitch/yaw movements when thecomponents are moved synchronously and opening/closing movements whenthe components are moved asynchronously or in an opposing manner).Extending the concepts described in reference to the surgical instrument300 to such an end effector would result in an instrument having fouractuator engagement members and four tensioning members to actuate thetwo degrees of freedom.

Referring to FIG. 9, the surgical instrument 300 can be selectivelycoupled with an instrument drive system 400. That is, the surgicalinstrument 300 can be coupled with the instrument drive system 400 foroperation as part of a computer-assisted tele-operated surgery system.Additionally, the surgical instrument 300 can be uncoupled from theinstrument drive system 400 (e.g., for replacement by another type ofsurgical instrument, for sterilization of the surgical instrument 300,etc.).

In some embodiments, the instrument drive system 400 can be mounted to amanipulator assembly, which can in turn be mounted to another structureor a base. The instrument drive system 400 can be interchangeablymounted to a manipulator assembly in some cases. That is, in someembodiments the instrument drive system 400 is designed for convenientdetachment from a manipulator assembly such that it is readilyinterchangeable with another instrument drive system. Therefore, theinstrument drive system 400 may also be referred to as a pod 400. Asused herein, the term “pod” indicates the interchangeable aspects ofsome instrument drive systems in relation to a manipulatorassembly—i.e., one pod may be removed from a manipulator assembly andreplaced with a second pod of the same, similar, or differentconfiguration. In some embodiments, the instrument drive system 400 isaffixed to a manipulator assembly in such a way that the instrumentdrive system 400 is not readily detachable or interchangeable.

In some embodiments, the surgical instrument 300 is slidably coupleablewith the instrument drive system 400. That is, the surgical instrument300 can be slidably extended distally and slidably retracted proximallyin relation to the instrument drive system 400.

In the depicted embodiment, the instrument drive system 400 includes afirst actuator 410, a second actuator 420, and a shaft actuator 430. Thefirst actuator 410 is releasably coupleable with the first actuatorengagement member 350. Hence, the first actuator 410 can induce atensile force in the first tensioning member 340. The second actuator420 is releasably coupleable with the second actuator engagement member370. Hence, the second actuator 420 can induce a tensile force in thesecond tensioning member 360. The actuators 410, 420 are shown in anon-detained engagement with the corresponding actuator engagementmembers 350, 370. Optionally, the actuators 410, 420 are in a detainedengagement with the corresponding actuator engagement members 350, 370,such as a latch. In a detained engagement, two objects are fixedtogether (releasably or otherwise) so that as one object moves, theother object correspondingly moves. In a non-detained engagement, thetwo objects are not fixed together, so that if one object moves towardthe other, the other object moves, but if one object moves away from theother, the other object will not move.

In light of the arrangement between the surgical instrument 300 and thefirst and second actuators 410 and 420 of the instrument drive system400 as described above, it can be envisioned that concerted modulationof the forces exerted from the first and second actuators 410 and 420 tothe first and second actuator engagement members 350 and 370,respectively, can result in controlled motion of the end effector 330 inits degree of freedom. Moreover, it can also be envisioned (as describedfurther below), that the tensions in the first and second tensioningmembers 340 and 360 can also be controlled by the concerted modulationof the forces exerted from the first and second actuators 410 and 420 tothe first and second actuator engagement members 350 and 370,respectively. Still further, it can also be envisioned that the tensionsin the first and second tensioning members 340 and 360 can be controlledby the concerted modulation of the forces exerted from the first andsecond actuators 410 and 420 to the first and second actuator engagementmembers 350 and 370, respectively, while the concerted modulation of theforces exerted from the first and second actuators 410 and 420 to thefirst and second actuator engagement members 350 and 370 alsoconcurrently cause desired movements of the end effector 330. Put moresimply, the tensions in the first and second tensioning members 340 and360 can be controlled to a desired amount of tensile force whilemovements of the end effector 330 are being made as desired. Thisconcept can be referred to herein as “dynamic tension control” or“dynamic tension and position control.”

Still referring to FIG. 9, the instrument drive system 400 also includesthe shaft actuator 430 that engages with a corresponding shaft actuatorengagement member on the surgical instrument in a non-detained ordetained engagement. An example of non-detained engagement is engagementwith a part of distal end portion 310 that acts as the shaft actuatorengagement member, as shown. An example of detained engagement isengagement with a latch, as described below. The shaft actuator 430releasably couples with the instrument shaft 302 for both detained andnon-detained engagement.

In some embodiments, the shaft actuator 430 releasably couples with theinstrument shaft 302 (or to a structure coupled to the instrument shaft302) using a latch mechanism. Accordingly, in some such embodiments,while the shaft actuator 430 is latched to the instrument 300, the shaftactuator 430 is able to exert either a distally-directed force or aproximally-directed force to distally extend or proximally retract theinstrument 300, as desired, in relation to the instrument drive system400. It should be understood that such a latch mechanism for couplingthe shaft actuator 430 to the instrument shaft 302 is not required inall embodiments. Further, in some embodiments the shaft actuator 430 isconfigured to only exert a distally-directed force to the instrument 300(i.e., not a proximally-directed force). The dynamic tension andposition control concepts described herein can still be performed whilethe shaft actuator 430 is configured to exert only a distally-directedforce to the instrument 300.

The actuators 410, 420, and 430 can be various types of actuators. Insome embodiments, the first actuator 410, a second actuator 420, and ashaft actuator 430 each comprise electrical motors that are coupled tolead screws that linearly drive nut members on the threads of the leadscrew. In some embodiments, the entire assembly of the surgicalinstrument 300 in combination with the instrument drive system 400 canbe driven together to result in a desired motion of the end effector,such as a rolling motion about the longitudinal axis of the surgicalinstrument 300.

Referring also to FIG. 10, a force diagram 500 can be used to furtherdescribe the structure and operations of the surgical instrument 300 incombination with the instrument drive system 400. The body 301 isrepresentative of the surgical instrument 300. Force f₁ isrepresentative of the force applied by the first actuator 410 to thefirst engagement member 350. Force f₂ is representative of the forceapplied by the second actuator 420 to the second engagement member 370.Force f_(s) is representative of the force applied by the shaft actuator430 to the instrument shaft 302.

Force f_(s) is directionally opposite to forces f₁ and f₂. Hence, in astatic context, force f_(s) is equal to the sum of forces f₁ and f₂. Ina dynamic context, if force f_(s) is greater than the sum of forces f₁and f₂, then the body 301 will move in the direction of force A.Conversely, if force f_(s) is less than the sum of forces f₁ and f₂,then the body 301 will move in the direction of forces f₁ and f₂.

Applying the principles described above regarding the force diagram 500to the analogous arrangement of the surgical instrument 300 incombination with the instrument drive system 400, the following conceptscan be envisioned. While the surgical instrument 300 is in a constantspatial relationship with the instrument drive system 400 (i.e., in astatic context), the sum of the forces exerted from the first and secondactuators 410 and 420 to the first and second actuator engagementmembers 350 and 370 equal the force exerted from the shaft actuator 430to the instrument shaft 302. In addition, while the sum of the forcesexerted from the first and second actuators 410 and 420 to the first andsecond actuator engagement members 350 and 370 are greater than theforce exerted from the shaft actuator 430 to the instrument shaft 302,the surgical instrument 300 will move proximally in relation to theinstrument drive system 400. Still further, while the sum of the forcesexerted from the first and second actuators 410 and 420 to the first andsecond actuator engagement members 350 and 370 are less than the forceexerted from the shaft actuator 430 to the instrument shaft 302, thesurgical instrument 300 will move distally in relation to the instrumentdrive system 400.

To be clear, the combinations of forces from the actuators 410, 420, and430 that cause the proximal and distal movements of the surgicalinstrument 300 in relation to the instrument drive system 400 involvethe sum of the forces exerted from the first and second actuators 410and 420 to the first and second actuator engagement members 350 and 370.Hence, it can be envisioned that the forces exerted from the first andsecond actuators 410 and 420 to the first and second actuator engagementmembers 350 and 370 can be equal to each other, or can differ from eachother while the sum is still a total amount that is appropriate toresult in a desired distal/proximal movement and/or orientation betweenthe surgical instrument 300 and the instrument drive system 400. Forexample, in the case when the forces exerted from the first and secondactuators 410 and 420 to the first and second actuator engagementmembers 350 and 370 differ from each other, a movement of end effector330 will result, and in the case when the forces exerted from the firstand second actuators 410 and 420 to the first and second actuatorengagement members 350 and 370 are equal to each other, the end effector330 will be stationary in relation to the instrument shaft 302. Again,it should be understood that, using the structure and operationalconcepts provided herein, distal/proximal movements of the surgicalinstrument 300 in relation to the instrument drive system 400 can bemade concurrently with movements of the end effector 300 in relation tothe instrument shaft 302. Moreover, both such movements can be madeconcurrently while the tensions in the first tensioning member 340 andthe second tensioning member 360 are maintained at a desired level oftensile force (e.g., within a target range of desired tensile force).

It should be understood that the force exerted by actuator 430 may bethe prime moving force, so that instrument 330 insertion and withdrawalis directly controlled by actuator 430, and actuators 410,420 applyforce sufficient to maintain tension in tension elements 340,360 and tomaintain or change end effector 330's orientation as actuator 430inserts and withdraws the instrument. And so, in one aspect actuator 430controls instrument 300's insertion and withdrawal location whileactuators 410,420 react to control tension on tension elements 340,360as the location changes. For example, when actuator 430 slightlyincreases force to insert the instrument shaft, the slight tensionincrease in tension elements 340,360 is sensed and so actuators 410,420decrease force to return tension elements 340,360 to the desired value.Alternatively, instrument 330 insertion and withdrawal is controlled byactuators 410,420,430 working in concert to control tension on tensionelements 340,360 which in turn controls instrument 300's insertion andwithdrawal location, and at the same time end effector 330's orientationis maintained or changed by actuators 410,420 working together tocontrol relative tension between tension elements 340,360. For example,when actuator 430 slightly increases force to insert the instrumentshaft, actuators 410,420 simultaneously decrease force to maintaintension in tension elements 340,360 at the desired value. It can beappreciated that these two tension-control aspects apply to a reversesituation in which actuators 410,420 act together to apply the primemoving force for insertion/withdrawal, with actuator 430 controllingtension in the tension members. And, it can be appreciated that thesetension-control aspects apply to more complicated movements in which theinstrument shaft is moved in insertion/withdrawal and the end effectoris moved in one or more degrees of freedom.

Referring also to FIGS. 11-13, the concepts described above can befurther described by examples using illustrations of the surgicalinstrument 300 in various positions in relation to the instrument drivesystem 400.

In a first example, the arrangement of FIG. 9 can be transitioned tothat of FIG. 11 by temporarily increasing the force exerted by the firstactuator 410 to the first actuator engagement member 350 in comparisonto the force exerted by the second actuator 420 to the second actuatorengagement member 370, while the sum of the two forces is held equal tothe force exerted by the shaft actuator 430 to the instrument shaft 302.In result, the end effector 330 will move in relation to the instrumentshaft 302 while the surgical instrument 300 is maintained in a constantspatial relationship (i.e., no distal and proximal movements) inrelation to the instrument drive 400. Such a movement can be made whilethe tensions in the first tensioning member 340 and the secondtensioning member 360 are maintained at a desired level of tensile force(e.g., within a target range of desired tensile force).

In a second example, the arrangement of FIG. 9 can be transitioned tothat of FIG. 12 by temporarily increasing the force exerted by the firstactuator 410 to the first actuator engagement member 350 in comparisonto the force exerted by the second actuator 420 to the second actuatorengagement member 370, while the sum of the two forces is temporarilyless than the force exerted by the shaft actuator 430 to the instrumentshaft 302. In result, the end effector 330 will move in relation to theinstrument shaft 302, and the surgical instrument 300 will extenddistally in relation to the instrument drive 400. Such movements can bemade while the tensions in the first tensioning member 340 and thesecond tensioning member 360 are maintained at a desired level oftensile force (e.g., within a target range of desired tensile force).

In a third example, the arrangement of FIG. 9 can be transitioned tothat of FIG. 13 by temporarily increasing the force exerted by the firstactuator 410 to the first actuator engagement member 350 in comparisonto the force exerted by the second actuator 420 to the second actuatorengagement member 370, while the sum of the two forces is temporarilygreater than the force exerted by the shaft actuator 430 to theinstrument shaft 302. In result, the end effector 330 will move inrelation to the instrument shaft 302, and the surgical instrument 300will retract proximally in relation to the instrument drive 400. Suchmovements can be made while the tensions in the first tensioning member340 and the second tensioning member 360 are maintained at a desiredlevel of tensile force (e.g., within a target range of desired tensileforce).

In a fourth example, the arrangement of FIG. 12 can be transitioned tothat of FIG. 13 by maintaining equal forces exerted by the firstactuator 410 to the first actuator engagement member 350 and by thesecond actuator 420 exerted to the second actuator engagement member370, while the sum of the two forces is temporarily greater than theforce exerted by the shaft actuator 430 to the instrument shaft 302. Inresult, the end effector 330 will not move in relation to the instrumentshaft 302, and the surgical instrument 300 will retract proximally inrelation to the instrument drive 400. Such a movement can be made whilethe tensions in the first tensioning member 340 and the secondtensioning member 360 are maintained at a desired level of tensile force(e.g., within a target range of desired tensile force).

In a fifth example, the arrangement of FIG. 13 can be transitioned tothat of FIG. 12 by maintaining equal forces exerted by the firstactuator 410 to the first actuator engagement member 350 and by thesecond actuator 420 exerted to the second actuator engagement member370, while the sum of the two forces is temporarily less than the forceexerted by the shaft actuator 430 to the instrument shaft 302. Inresult, the end effector 330 will move in relation to the instrumentshaft 302, and the surgical instrument 300 will extend distally inrelation to the instrument drive 400. Such a movement can be made whilethe tensions in the first tensioning member 340 and the secondtensioning member 360 are maintained at a desired level of tensile force(e.g., within a target range of desired tensile force).

Examples so far have illustrated the drive unit's first and secondactuators applying a proximal compressive force against theircorresponding first and second actuator engagement members, and thedrive unit's shaft actuator applying a distal compressive force againstthe instrument shaft. But, in another aspect the orientations of theseforces are reversed, so that the drive unit's first and second actuatorsapply a distal compressive force against their corresponding first andsecond actuator engagement members, and the drive unit's shaft actuatorapplies a proximal compressive force against the instrument shaft. Inthis aspect, the tensioning members may be routed over pulleys so thatdistal movement of an actuator engagement member causes tension in thecorresponding tension member and associated end effector movement. Or,the tensioning members may be replaced with compression members, such aspush rods coupled to the end effector, so that distal movement of anactuator engagement member causes compression in the correspondingcompression member and associated end effector movement.

Referring to FIG. 14, in some embodiments the forces exerted by theactuators 410, 420, and/or 430 to the surgical instrument 300 can bedetected by the use of one or more force detection devices. Theoutput(s) of such force detection devices can be used for controllingthe actuators 410, 420, and/or 430 (i.e., to control movements of thesurgical instrument 300 and/or to control tensions of the first andsecond tensioning members 340 and 360).

In a first non-limiting example, the depicted arrangement includes aload cell 510 type of force sensor disposed at or near the juncturebetween the first actuator 410 and the first actuator engagement member350. In another example, the depicted arrangement includes a load cell520 type of force sensor disposed near the connection between the firstactuator 410 and a structural member 401 of the instrument drive system400. In some embodiments, the instrument drive system 400 can be a pod(i.e., readily interchangeable in relation to mounting on a manipulatorassembly).

In some embodiments, other sensors and/or other devices can be used todetect the forces exerted by the actuators 410, 420, and/or 430 to thesurgical instrument 300. For example, in some embodiments strain gaugescan be located on the actuator engagement members, e.g., the firstactuator engagement member 350. In another embodiment, the electricalcurrent drawn by electric motors of the actuators 410, 420, and/or 430can be measured and used as an indication of the forces exerted by theactuators 410, 420, and/or 430 to the surgical instrument 300. In someembodiments, a combination of such force detection devices andtechniques can be used.

Referring to FIGS. 15-18, an example surgical instrument 600 that can beused as part of a computer-assisted tele-operated surgery systemincludes a proximal end portion 610, an instrument shaft 640, and an endeffector 650. The surgical instrument 600 is an example of a surgicalinstrument that is configured in accordance with the schematic diagrams(e.g., FIGS. 8, 9, and 11-14) described above. Hence, the surgicalinstrument 600 can function in accordance with the schematic diagramsdescribed above.

The instrument shaft 640 extends distally from the proximal end portion610. The instrument shaft 640 includes a distal end portion to which theend effector 650 is coupled. The instrument shaft 640 defines alongitudinal axis 602 of the surgical instrument 600, along which theinstrument is inserted into and withdrawn from the patient.

The end effectors (e.g., end effector 650) of the surgical instrumentsdescribed herein can be any type of surgical end effector (e.g.,graspers, cutters, cautery instruments, staplers, forceps, cameras,etc.). The end effectors (e.g., end effector 650) of the surgicalinstruments described herein can have one or multiple degrees of freedom(e.g., two, three, four, five, six, seven, eight, or more than eightdegrees of freedom). Moreover, it should be understood that the conceptsdescribed herein in the context of a single degree of freedom of the endeffectors can be extended to each degree of freedom of multiple degreesof freedom of the surgical instrument 600, and of other types ofsurgical instruments for computer-assisted tele-operated surgerysystems.

In the depicted embodiment, the proximal end portion 610 includes ahandle 612, a plurality of actuator engagement members (depicted heredisposed in a grouping 630 at a same longitudinal location along thelongitudinal axis 602), and an instrument shaft actuator engagementmember 620. The plurality of actuator engagement members 630 are movablycoupled to the proximal end portion 610. In the depicted embodiment, theplurality of actuator engagement members 630 are slidably coupled to theproximal end portion 610 such that the plurality of actuator engagementmembers 630 can translate parallel to the longitudinal axis 602. Theinstrument shaft actuator engagement member 620 is coupled to theproximal end portion 610. In the depicted embodiment, instrument shaftactuator engagement member 620 is pivotably coupled to the proximal endportion 610.

The handle 612 extends radially from the longitudinal axis 602. In thedepicted embodiment, the handle 612 is the portion of proximal endportion 610 and of the entire surgical instrument 600 that radiallyextends the farthest. The handle 612 is configured to facilitate manualgripping and manipulation of the surgical instrument 600.

In some embodiments, the handle 612 includes an indicium that identifiesthe type of the surgical instrument 600. For example, in the depictedembodiment the handle 612 includes a visible indicium that is an icon614 that depicts that the surgical instrument 600 is a grasper device.In some embodiments, the handle 612 includes a machine-readableindicium, such as an RFID chip or NFC tag that can be used to store andcommunicate information pertaining to the surgical instrument 600. Forexample, such information pertaining to the surgical instrument 600 caninclude, but is not limited to, a unique identification or serialnumber, the type of instrument, the number of times the instrument hasbeen used for one or more surgical procedures, and the like.

In some embodiments, the handle 612 optionally includes one or moremagnets that an instrument drive system can use to sense the presence ofthe surgical instrument 600 mounted in the instrument drive system.

The proximal end portion 610 includes the plurality of actuatorengagement members. As depicted the actuator engagement members aredisposed in a grouping 630 at a common longitudinal location along thelongitudinal axis 602. Optionally they may be at two or morelongitudinal locations along longitudinal axis 602 so that a firstcoupled pair of actuator engagement members is at a first longitudinallocation and a second coupled pair of actuator engagement members is ata second longitudinal location, or each actuator engagement member of acoupled pair is at a different longitudinal location. The actuatorengagement members are configured to releasably engage with actuatorswhich drive the actuator engagement members and corresponding movementsof the end effector 650 as described above in reference to FIGS. 8-14.As shown, each individual actuator engagement member slideslongitudinally in a corresponding individual longitudinal slot inproximal end portion 610. In other optional aspects, however, anindividual actuator engagement member may have a different configuration(e.g., a lever, a rotating piece such as a disk or gear, a cam surface,and the like). As shown, all individual actuator engagement membersextend radially outward slightly beyond the outer perimeter of proximalend portion 610 so that the associated actuators to not extend intoproximal end portion 610. Alternatively, one or more individual actuatorengagement members may not extend to or beyond the outer perimeter ofproximal end portion (e.g., they are positioned slightly inside proximalend portion 610) so they are less prone to damage or do not snag on anobject. In this alternative configuration, the associated actuatorsextend slightly into proximal end portion 610 to engage the instrument'sactuator engagement members. All actuator engagement members may havethe same configuration, or two or more actuator engagement memberconfigurations may be used in a single instrument, as long as theactuator engagement members comply with the principles of operationdescribed with reference to FIGS. 8-14. In the depicted embodiment thefollowing example actuator engagement members are included: 632 a, 632b, 634 a, 634 b, 636 a, 636 b, and 638. More or fewer actuatorengagement members may be included in some embodiments.

The actuator engagement members, e.g., actuator engagement members 632a, 632 b, 634 a, 634 b, 636 a, 636 b, and 638, are coupled to tensioningmembers (e.g., comprising flexible cables that can be routed over smallradius pulleys (e.g., 2-10 mm scale), semi-flexible cables that cannotbe routed over small radius pulleys, rigid hypo-tubes, pull rods, etc.)that extend along the instrument shaft 640 and that are movably coupledto the end effector 650. Hence, movements of the actuator engagementmembers result in movements of the end effector 650.

In some cases, the actuator engagement members are paired (e.g.,actuator engagement members 632 a and 632 b, actuator engagement members634 a and 634 b, and actuator engagement members 636 a and 636 b) suchthat moving one actuator engagement member of the pair proximallyresults in a corresponding distal movement of the other actuatorengagement member of the pair. For example, moving actuator engagementmember 632 a proximally results in a corresponding distal movement ofactuator engagement member 632 b, and moving actuator engagement member632 b proximally results in a corresponding distal movement of actuatorengagement member 632 a. In other words, actuator engagement memberpairs move in opposition to each other.

When the structure of the surgical instrument 600 includes actuatorengagement members (e.g., actuator engagement members 632 a, 632 b, 634a, 634 b, 636 a, 636 b, and 638) that are coupled to flexible tensioningcables, it can be envisioned that distal movements of the actuatorengagement members without a corresponding proximal movement of a pairedactuator engagement member will not move the end effector 650. Rather,the flexible tensioning cable attached to the actuator engagement memberbeing moved distally would simply become flaccid (due to the limitedcolumn strength/rigidity of a flexible tensioning cable). Hence, it canbe said that, in some embodiments, the actuator engagement members 632a, 632 b, 634 a, 634 b, 636 a, 636 b, and 638 are configured to move theend effector 650 in response to receiving a proximally-directed force,and are configured to not move the end effector 650 in response toreceiving a distally-directed force. However, in some embodiments one ormore of the actuator engagement members (e.g., the actuator engagementmember 638 which is not paired with another actuator engagement member)are configured to move the end effector 650 both ways (proximally anddistally). That is, such actuator engagement members optionally drive aflexible or semi-flexible member in a manner similar to Bowdin cableoperation, or drive a rigid member in a manner similar to push/pull rodoperation. For example, in some embodiments the actuator engagementmember 638 may be configured to operate a blade of the end effector 650or a clamp in the case that the end effector 650 includes a stapler. Inthe example of the blade, the actuator engagement member 638 worksopposite to a spring (cut under drive, spring back). In the example ofthe stapler, the actuator engagement member 638 moves distally to drivethe firing sequence, while the grip-open actuation returns the actuatorengagement member 638 proximally.

Still referring to FIGS. 15-18, in the depicted arrangement of surgicalinstrument 600, the actuator engagement members 632 a, 632 b, 634 a, 634b, 636 a, 636 b, and 638 are all positioned at the same longitudinallocation along the longitudinal axis 602 of the surgical instrument.However, during use of the surgical instrument 600, the actuatorengagement members 632 a, 632 b, 634 a, 634 b, 636 a, 636 b, and 638 aremoved to various longitudinal locations along the longitudinal axis 602of the surgical instrument. This is described further by the followingexample.

When the surgical instrument 600 is coupled with an instrument drivesystem, actuators of the instrument drive system will releasably couplewith the actuator engagement members 632 a, 632 b, 634 a, 634 b, 636 a,636 b, and 638. For example, the actuators will engage the actuatorengagement members by moving proximally until a reaction force thatindicates engagement is sensed. For paired actuator engagement members632 a and 632 b, a first actuator moves proximally until actuatorengagement member 632 a is engaged, and a second actuator movesproximally until actuator engagement member 632 b is engaged. The firstand second actuators may then adjust the longitudinal position of thecorresponding actuator engagement members 632 a and 632 b to set adesired tension in corresponding paired tension members coupled to thedistal end component so that all slack or backlash is removed from thedrive train between the actuator engagement members and thecorresponding distal end component and so that movement of the actuatorengagement members results in immediate movement of the correspondingdistal end component. That is, one or more instrument drive systemactuators engage the corresponding one or more instrument actuatorengagement members and set a dynamic preload tension (which may be inaddition to the static preload tension described below) in the one ormore instrument tension members between the one or more actuatorengagement members and the corresponding instrument distal end component(e.g., wrist or end effector component).

Then, in response to input (such as from surgeon console 40 of FIG. 2),the actuators of the instrument drive system correspondingly move someor all of the actuator engagement members (e.g., the actuator engagementmembers 632 a, 632 b, 634 a, 634 b, 636 a, and/or 636 b) proximally toinitiate desired movements of the end effector 650 or other distal endcomponent. For example, for paired actuator engagement members 632 a and632 b, a first actuator of the instrument drive system may move actuatorengagement member 632 a proximally. In concert with that proximalmovement of actuator engagement member 632 a, a second actuator of theinstrument drive system may resist distal movement of actuatorengagement member 632 b, thus keeping tension on actuator engagementmember 632 b's corresponding tension member, but still allows actuatorengagement member 632 b to move distally. The second actuator'sresistance to actuator engagement member 632 b's distal movement ismodulated to maintain a desired tension in the tensioning members thatcorrespond to the actuator engagement members 632 a and 632 b. Thisoperation is performed in accordance with the dynamic tensioningconcepts described above in reference to FIGS. 8-14.

In one aspect, the control system controls the tension in each of thepaired tension members to be equal as the tension members move thecorresponding end effector. In another aspect, however, the controlsystem controls the tension in the tension members to cause a requiredload force in the loaded tension member and to maintain a minimumtension on the non-loaded tension member.

To explain this differential force aspect by example, consider pairedactuator engagement members 632 a and 632 b. When their associated endeffector is at a neutral position (e.g., centered on the instrument'slongitudinal axis and not engaged with another object), not moving, andnot experiencing a load, the control system may cause an equal force tobe applied to actuator engagement members 632 a and 632 b. This equalforce is at or above a minimum force required to remove backlash fromthe tension member connections between the end effector and the actuatorengagement members for effective control. But, the equal force is keptlow in order to reduce friction and tension loads that result inmechanical wear.

To move the associated end effector, the control system moves theactuator engagement members 632 a and 632 b in opposite directions. Theend effector movement caused by the proximal motion of actuatorengagement member 632 a may be unresisted (e.g., the end effector movesfreely) or resisted (e.g., the end effector moves against tissue oranother part of the end effector, such as a jaw moving against anotherjaw in grip). Friction in the drive train may also cause a load thatrequires a higher force be applied to actuator engagement member 632 athan is required to keep the end effector under effective control at aneutral position. Thus, the actuator associated with actuator engagementmember 632 a must increase its force against actuator engagement member632 to either continue to move the corresponding end effector or tomaintain the corresponding end effector's force against the resistance.In this situation, however, there is no need for the actuator associatedwith the paired actuator engagement member 632 b to exert a force onactuator engagement member 632 b that is the same as the force exertedon actuator engagement member 632 a. What is required is that the forceexerted on actuator engagement member 632 b be at or above a minimumthreshold necessary to keep the associated tension member from goingslack or deviating from its path, such as by leaving a pulley.

As a further illustration, if the control system causes actuatorengagement member 632 a to receive a maximum allowable force from itsassociated drive unit actuator in order to produce a maximum force atthe corresponding end effector (e.g., to produce a maximum possible endeffector grip force), then the control system may cause actuatorengagement member 632 b to receive only a minimum force required toensure that its associated tension member does not go slack and does notdisengage from its proper routing, or to receive a force between thisminimum force and the force applied to actuator engagement member 632 a.And, although this aspect applies for maximum force applied to actuatorengagement member 632 a, it also applies when lower forces are appliedso that again the conflicting tension caused by the force againstactuator engagement member 632 b is minimized. It should be understoodthat if the end effector is then to be moved in the opposite direction,the required load force is applied against actuator engagement member632 b, and the required tension-maintaining force is applied againstactuator engagement member 632 a. It should also be understood that thisdifferential force aspect applies if compression is used to move an endeffector instead of tension, so that any unnecessary compression forceis reduced or minimized.

In some embodiments of surgical instrument 600, pre-load tensioningmembers (e.g., springs 633) may be included to maintain a minimaltension in the tensioning members while the surgical instrument 600 isseparated from an instrument drive system—a static preload tension. Suchminimal pre-tensioning may help ensure that the tensioning membersremain oriented and routed within the surgical instrument 600 asdesired. In the depicted embodiment, compression springs 633 apply aproximally-directed force to the actuator engagement members 632 a, 632b, 634 a, 634 b, 636 a, 636 b, and 638 to maintain a minimal tension inthe tensioning members while the surgical instrument 600 is separatedfrom an instrument drive system. In some embodiments, other types ofpre-load tensioning members may be used such as, but not limited to,flexures created as part of shaft 640 or proximal end portion 610,extension springs, torsion springs, leaf springs, and the like. Further,in embodiments that incorporate compression members in place oftensioning members, pre-load compression members similar to thesepre-load tensioning members may be used to eliminate mechanical backlashin the drive trains between actuator engagement members and the endeffector.

Still referring to FIGS. 15-18, proximal end portion 610 includes theinstrument shaft actuator engagement member 620. The instrument shaftactuator engagement member 620 is used for releasably coupling theproximal end portion 610 to an actuator of an instrument drive system.Since the instrument shaft 640 is rigidly coupled to the proximal endportion 610, the instrument shaft actuator engagement member 620 alsoreleasably couples the instrument shaft 640 to an actuator of aninstrument drive system. This concept of using the instrument shaftactuator engagement member 620 to couple an actuator to the proximal endportion 610 and the instrument shaft 640 was introduced above by theschematic diagrams and the descriptions thereof (e.g., by FIG. 9 whichincludes the shaft actuator 430 that can releasably couple with theinstrument shaft 302). Hence, the instrument shaft actuator engagementmember 620, when coupled with an actuator of an instrument drive system,is used for moving the entire surgical instrument 600 proximally and/ordistally in relation to the instrument drive system. In addition (asdescribed in reference to the force diagram of FIG. 10), the instrumentshaft actuator engagement member 620, when coupled with an actuator ofan instrument drive system, is used for balancing proximally directedforces applied by actuators to the actuator engagement members 632 a,632 b, 634 a, 634 b, 636 a, 636 b, and 638.

In the depicted embodiment, the actuator engagement members 632 a, 632b, 634 a, 634 b, 636 a, 636 b, and 638 are configured to receiveproximally-directed forces from the actuators of an instrument drivesystem but are not configured to receive distally-directed forces fromthe actuators of an instrument drive system. In other words, theactuator engagement members 632 a, 632 b, 634 a, 634 b, 636 a, 636 b,and 638 are not detained (not immovably coupled with; a non-detainedengagement) to the actuators of an instrument drive system. Stateddifferently, the actuator engagement members 632 a, 632 b, 634 a, 634 b,636 a, 636 b, and 638 are each configured for directly facilitating(causing) movement the end effector 650 in response to receiving aproximally-directed force from a corresponding actuator, and are eachnot configured for directly facilitating movement the end effector 650in response to receiving a distally-directed force from a correspondingactuator. In contrast, in the depicted embodiment the instrument shaftactuator engagement member 620 is configured to directly facilitatemovement of the entire surgical instrument 600 proximally in response toreceiving a proximally-directed force, and is configured to directlyfacilitate movement of the entire surgical instrument 600 distally inresponse to receiving a distally-directed force. That is the casebecause the instrument shaft actuator engagement member 620 isconfigured to be releasably detained to an actuator of an instrumentdrive system. For example, in the depicted embodiment the instrumentshaft actuator engagement member 620 is a latch mechanism that can beused to releasably detain the proximal end portion 610 and theinstrument shaft 640 to an actuator of an instrument drive system. Itshould be understood that the use of a latch mechanism for theinstrument shaft actuator engagement member 620 is not required in allembodiments, and other suitable coupling mechanisms at various locationson the instrument may be used.

Further, in some embodiments the instrument shaft actuator engagementmember 620 is configured such that the instrument drive system onlyexerts distally-directed forces to the surgical instrument 600 (i.e.,not proximally-directed forces). The dynamic tension and positioncontrol concepts described herein can still be performed in such a casewhere the instrument shaft actuator engagement member 620 is configuredto receive only a distally-directed force from the instrument drivesystem. In this aspect, distally-directed force on the instrument'sshaft actuator engagement member is balanced with proximally-directedforces on the instrument's actuator engagement members.

Referring particularly to FIG. 18, in some embodiments the surgicalinstrument 600 is configured with one or more connectors or contacts forinputting energy to the end effector 650 (e.g., energy forcauterization). For example, in some embodiments the surgical instrumentmay be configured to use monopolar RF, bi-polar RF, or another energyform. In such a case, in some embodiments the one or more connectors arelocated on a proximal area 613 of the handle 612. Such a location canallow the one or more connectors to be readily accessible for connectionwith one or more cables that supply the energy. Such a location can alsoallow the connections to be made and/or disconnected while the surgicalinstrument 600 is coupled with an instrument drive system.

Referring to FIG. 19, the surgical instrument 600 can be selectivelycoupled with a compatible instrument drive system 700 (also referred toas pod 700) that defines a longitudinal axis 702 of a space configuredto receive the surgical instrument 600. In accordance with a typicalimplementation for computer-assisted tele-operated surgery, theinstrument drive system 700 can be coupled to a manipulator assembly 800with multiple degrees of freedom. In some embodiments, the pod 700 isreadily detachable from the manipulator assembly 800 such that the pod700 can be conveniently interchanged with another pod. The manipulatorassembly 800 can be attached to a supporting structure of various types(e.g., refer to FIGS. 3 and 4). The instrument shaft 640 can slidablyextend through a cannula 740 that is optionally releasably mounted tothe manipulator assembly 800 or to the instrument drive system 700.

In the depicted embodiment, the surgical instrument 600 can bereleasably coupled with the instrument drive system 700 by moving thesurgical instrument 600 distally into an opening at the proximal end 704of the instrument drive system 700. In particular, the longitudinal axis602 of the surgical instrument 600 can first be aligned with thelongitudinal axis 702 of the instrument drive system 700. Then thesurgical instrument 600 can be slid distally in relation to theinstrument drive system 700 until the instrument shaft engagement member620 couples with the instrument drive system 700.

At least portions of the handle 612 and the instrument shaft engagementmember 620 extend farther radially than adjacent portions of theinstrument drive system 700 while the surgical instrument is coupledwith the instrument drive system, so that handle 612 protrudes out ofpod 700. Accordingly, the handle 612 and instrument shaft engagementmember 620 are accessible to the hands of a user. Such accessibility canadvantageously facilitate ready decoupling of the surgical instrument600 from the instrument drive system 700.

Although not visible, the instrument drive system 700 includes multipleactuators (schematically depicted in FIGS. 9 and 11-14) that releasablycouple with the actuator engagement members 632 a, 632 b, 634 a, 634 b,636 a, 636 b, and 638 while the surgical instrument 600 is coupled withthe instrument drive system 700. In some embodiments, the actuators arelinear actuators that include lead screws and lead screw nut members,and other suitable linear actuators (e.g., chain, belt, hydraulic,pneumatic, electromagnetic, and the like) may be used. In someembodiments, non-linear actuators such as rotary actuators, orcombinations of linear and non-linear actuators, may be used to producethe antagonistic force aspects as described. In some embodiments, one ormore force sensors are included in the instrument drive system 700 bywhich forces applied to the actuator engagement members 632 a, 632 b,634 a, 634 b, 636 a, 636 b, and/or 638 can be determined and fed back tothe processor 43 (FIG. 2).

In some embodiments, the entirety of the surgical instrument 600 coupledto the instrument drive system 700 can be rotated or rolled about thelongitudinal axes 602 and 702 as a single unit. The instrument actuatorengagement member 620, when coupled to pod 700 either via an instrumentshaft insertion/withdrawal actuator or directly to pod 700, is used tosecure the instrument shaft during roll around longitudinal axis 602 aspod 700 rotates around its longitudinal axis 702. In addition, handle612 may provide extra support against pod 700 for roll. A motor at thedistal end of pod 700, either inside pod 700 or part of manipulator 800,rotates the assembly of pod 700 and instrument 600. Thus the instrumentshaft, and the distal end effector, may be simultaneouslyinserted/withdrawn and rolled.

Referring to FIG. 20, the surgical instrument actuation pod 700 is shownin isolation from the surgical instrument 600 and the manipulatorassembly 800. The pod 700 includes the proximal end 704 and a distal end706. The pod 700 defines the longitudinal axis 702 along which asurgical instrument (or other device such as an endoscopic camera) canbe installed.

In the depicted embodiment, the pod 700 includes a proximal end plate705, a distal end plate 707, and a housing 710. The housing 710 extendsbetween the proximal end 704 and the distal end 706.

In the depicted embodiment, the proximal end plate 705 is a C-shapedplate, while the distal end plate 707 is a fully circumferential platethat defines an open center area. The opening of the C-shape in theproximal end plate 705 aligns with a slot opening 712 defined by thehousing 710. The slot opening 712 and the opening in the C-shapedproximal end plate 705 provide clearance for the handle 612 of thesurgical instrument 600 to project radially from the housing 710 whilethe surgical instrument 600 is coupled with the instrument drive system700.

As described further below, the proximal end plate 705 and the distalend plate 707 are structural components of a frame of the pod 700.Optionally, however, the end plates may be integrated with the housingor other pod component, either as part of or apart from the frame. Inthe depicted embodiment, the frame also includes a pod rotation gear 708located at the distal end 706. The pod rotation gear 708 meshes with andis driven by a drive gear of the manipulator assembly 800 when the pod700 is coupled with the manipulator assembly 800. When the pod rotationgear 708 is driven, the entire pod 700 rotates about the longitudinalaxis 702, which is roll axis for the pod. When the surgical instrument600 is engaged with the pod 700 it is aligned with this roll axis, andso the surgical instrument 600 also rotates or rolls about thelongitudinal axis 702 as the pod rotation gear 708 is driven by a drivegear of the manipulator assembly 800. That is, rolling the pod aroundits longitudinal axis rotates the instrument shaft, which in turnintroduces roll to the instrument end effector. As such, the pod'slongitudinal axis 702 is coincident with the instrument shaft's rollaxis when the instrument is mounted in the pod, and the pod'slongitudinal axis 702 is also coincident with the instrument's insertionand withdrawal axis as the instrument inserts into and withdraws from apatient in relation to the pod.

Referring to FIG. 21, an exploded view of the surgical instrumentactuation pod 700 provides visualization of the pod's components thatare contained within the housing 710. As will be described in moredetail, the pod 700 includes a plurality of motors 720, a plurality oflead screws 730, a plurality of threaded nuts 740, and a plurality ofanti-rotation shafts 750. Throughout this description pod embodimentsare generally described as including motors, lead screws, and threadednuts, but it should be understood that this assembly is an illustrationof any equivalent linear actuator that can produce the required linearmotion, such as motor-driven ball screws, linear actuators, piezomotors, and the like. Accordingly, the motor, lead screw, and nutassemblies are examples of linear actuators that engage with thesurgical instrument's actuation engagement members to function asdescribed above.

In the depicted embodiment, the plurality of motors 720 are mounted atthe distal end of the pod and arranged concentrically around thelongitudinal axis 702. As shown, motors 720 are optionally mounted todistal end plate 707. In the depicted embodiment, no motors are mountedat the proximal end of the pod, for example to the proximal end plate705.

Each lead screw of the plurality of lead screws 730 is driven by acorresponding one of the plurality of motors 720. The lead screws 730extend distally to proximally in the pod around the center at which theinstrument is positioned. In the embodiment shown, the lead screws 730are rotatably coupled at their proximal ends to the proximal end plate705, and are rotatably coupled at their distal ends to the distal endplate 707. Optionally the lead screws are coupled to correspondingproximal ends of the motors, or to another generally distal structuralsupport in the pod.

Each threaded nut of the plurality of threaded nuts 740 is threadablyengaged with a corresponding one of the plurality of lead screws 730.Hence, the plurality of threaded nuts 740 translate parallel to thelongitudinal axis 702 as the plurality of lead screws 730 are rotatablydriven by the plurality of motors 720.

The plurality of anti-rotation shafts 750 extend between the proximalend plate 705 and the distal end plate 707, and they are slidablyengaged with the plurality of threaded nuts 740. Accordingly, theplurality of anti-rotation shafts 750 constrain the plurality ofthreaded nuts 740 from rotating as the plurality of lead screws 730rotate. As a result, each nut translates along its corresponding leadscrew as the lead screw rotates.

One or more electronic circuit boards (not shown) for operation of thepod 700 may be included within the housing 710. Such circuit boards maybe mounted to the end plates 707 and/or 705 for example. In someembodiments, one or more circuit boards may be located just above one ormore of the motors 720. These locations of circuit boards within thehousing 710 should not be deemed as limiting, and one or more circuitboards may be additionally or alternatively located in various otherpositions within the housing 710. Alternatively, one or more circuitboards may be located outside the pod, and an electronic connectionbetween the one or more boards and the pod motors accommodates podrotation.

Referring to FIGS. 22-25, the depicted embodiment includes eight motors720 a, 720 b, 720 c, 720 d, 720 e, 720 f, 720 g, and 720 h. The depictedembodiment also includes eight lead screws 730 a, 730 b, 730 c, 730 d,730 e, 730 f, 730 g, and 730 h. Each motor 720 a, 720 b, 720 c, 720 d,720 e, 720 f, 720 g, and 720 h is coupled to a drive gear 722 (FIG. 23)that meshes with a respective driven gear 732 (FIGS. 23 and 25) coupledto a corresponding lead screw 730 a, 730 b, 730 c, 730 d, 730 e, 730 f,730 g, and 730 h. Accordingly, each of the motors 720 a, 720 b, 720 c,720 d, 720 e, 720 f, 720 g, and 720 h can bi-directionally rotate itscorresponding one the lead screws 730 a, 730 b, 730 c, 730 d, 730 e, 730f, 730 g, and 730 h. That is, motor 720 a can bi-directionally rotatelead screw 730 a; motor 720 b can bi-directionally rotate lead screw 730b; motor 720 c can bi-directionally rotate lead screw 730 c; motor 720 dcan bi-directionally rotate lead screw 730 d; motor 720 e canbi-directionally rotate lead screw 730 e; motor 720 f canbi-directionally rotate lead screw 730 f; motor 720 g canbi-directionally rotate lead screw 730 g; and motor 720 h canbi-directionally rotate lead screw 730 h.

Although the depicted embodiment includes eight motor and leadscrewpairs, some embodiments include more than eight, or fewer than eight,motor and leadscrew pairs, depending on the number of required controlinputs for the various instruments to be mounted in the pod for surgery.For example, in some embodiments two, three, four, five, six, seven,nine, ten, eleven, twelve, or more than twelve motor and leadscrew pairsare included in an instrument actuation pod. All such variations arewithin the scope of this disclosure.

In some embodiments, the pod 700 also includes one or more motors thatdrive rotary motion of the pod 700 in relation to the manipulatorassembly 800—the roll about the longitudinal axis 702 described above.Alternatively, or additionally, in some embodiments one or more motorsfor driving roll motions of the pod 700 in relation to the manipulatorassembly 800 may be mounted to the manipulator assembly 800.

Positioning the motors distally within the pod advantageously positionsthe pod's center of mass close to the manipulator that supports the pod.In addition, other pod components (gears, load bearings, controlcircuits, sensors, etc.) are advantageously distally arranged so thatthe pod's center of mass is close to the supporting manipulator. Bykeeping the center of mass close to the manipulator, inertia isminimized. As a result, manipulator control of the instrument mounted inthe pod may be faster, smoother, and more precise than if the center ofmass is positioned farther from the manipulator. In addition, smalleractuator motors for the manipulator may be used.

Each lead screw 730 a, 730 b, 730 c, 730 d, 730 e, 730 f, 730 g, and 730h has a threaded nut 740 a, 740 b, 740 c, 740 d, 740 e, 740 f, 740 g,and 740 h that is threadably coupled to it. That is, lead screw 730 a isthreadably coupled to threaded nut 740 a; lead screw 730 b is threadablycoupled to threaded nut 740 b; lead screw 730 c is threadably coupled tothreaded nut 740 c; lead screw 730 d is threadably coupled to threadednut 740 d; lead screw 730 e is threadably coupled to threaded nut 740 e;lead screw 730 f is threadably coupled to threaded nut 740 f; lead screw730 g is threadably coupled to threaded nut 740 g; and lead screw 730 his threadably coupled to threaded nut 740 h.

As illustrated in FIG. 22, for example, all of the threaded nuts 740 a,740 b, 740 c, 740 d, 740 e, 740 f, 740 g, and 740 h are concurrentlypositionable at one or more common positions along the longitudinal axis702. While the pod 700 is in use, the position of individual threadednuts 740 a, 740 b, 740 c, 740 d, 740 e, 740 f, 740 g, and 740 h willlongitudinally translate parallel to longitudinal axis 702 in order tomove a surgical instrument and its components (e.g., surgical instrument600 described above) in response to surgeon input. Hence, the threadednuts 740 a, 740 b, 740 c, 740 d, 740 e, 740 f, 740 g, and 740 h will notalways share (but can share) a common longitudinal position along thelongitudinal axis 702.

In the depicted embodiment, the pod 700 also includes four anti-rotationshafts 750 a-b, 750 c-d, 750 e-f, and 750 g-h. The anti-rotation shafts750 a-b, 750 c-d, 750 e-f, and 750 g-h extend proximally, such asbetween the proximal end plate 705 and the distal end plate 707 asshown. In some embodiments, the anti-rotation shafts 750 a-b, 750 c-d,750 e-f, and 750 g-h are attached to the proximal end plate 705 and thedistal end plate 707 such that the anti-rotation shafts 750 a-b, 750c-d, 750 e-f, and 750 g-h serve as longitudinally-extending structuralframe members of the pod 700.

In the depicted embodiment, each anti-rotation shaft 750 a-b, 750 c-d,750 e-f, and 750 g-h is slidably coupled with two of the threaded nuts740 a, 740 b, 740 c, 740 d, 740 e, 740 f, 740 g, and 740 h. Moreparticularly, in the depicted embodiment each anti-rotation shaft 750a-b, 750 c-d, 750 e-f, and 750 g-h is slidably coupled with an adjacentpair of the threaded nuts 740 a, 740 b, 740 c, 740 d, 740 e, 740 f, 740g, and 740 h. That is, anti-rotation shaft 750 a-b is slidably coupledwith threaded nuts 740 a and 740 b; anti-rotation shaft 750 c-d isslidably coupled with threaded nuts 740 c and 740 d; anti-rotation shaft750 e-f is slidably coupled with threaded nuts 740 e and 740 f; andanti-rotation shaft 750 g-h is slidably coupled with threaded nuts 740 gand 740 h. In the depicted embodiment, each anti-rotation shaft 750 a-b,750 c-d, 750 e-f, and 750 g-h is slidably coupled with no more than twoof the threaded nuts 740 a, 740 b, 740 c, 740 d, 740 e, 740 f, 740 g,and 740 h. Further, in the depicted embodiment each of the threaded nuts740 a, 740 b, 740 c, 740 d, 740 e, 740 f, 740 g, and 740 h is slidablycoupled with only one of the anti-rotation shafts 750 a-b, 750 c-d, 750e-f, or 750 g-h.

The anti-rotation shafts 750 a-b, 750 c-d, 750 e-f, and 750 g-h preventrotations of the threaded nuts 740 a, 740 b, 740 c, 740 d, 740 e, 740 f,740 g, and 740 h while allowing longitudinal translations of thethreaded nuts 740 a, 740 b, 740 c, 740 d, 740 e, 740 f, 740 g, and 740h. Because the anti-rotation shafts 750 a-b, 750 c-d, 750 e-f, and 750g-h are slidably coupled with the threaded nuts 740 a, 740 b, 740 c, 740d, 740 e, 740 f, 740 g, and 740 h, rotations of the lead screws 730 a,730 b, 730 c, 730 d, 730 e, 730 f, 730 g, and 730 h will cause thethreaded nuts 740 a, 740 b, 740 c, 740 d, 740 e, 740 f, 740 g, and 740 hto longitudinally translate along the longitudinal axes of the leadscrews 730 a, 730 b, 730 c, 730 d, 730 e, 730 f, 730 g, and 730 h.

Four anti-rotation shafts-one for every two threaded nuts—are used inthe depicted embodiment in order to keep the pod's center of mass asdistal-most as possible, as described above. A smaller ratio ofanti-rotation shafts to threaded nuts may be used, however. And althoughthe depicted embodiment uses the anti-rotation shafts 750 a-b, 750 c-d,750 e-f, and 750 g-h to ensure longitudinal translations of the threadednuts 740 a, 740 b, 740 c, 740 d, 740 e, 740 f, 740 g, and 740 h inresponse to rotations of the lead screws 730 a, 730 b, 730 c, 730 d, 730e, 730 f, 730 g, and 730 h, in some embodiments other mechanisms areused. For example, in some alternative embodiments the housing 710(FIGS. 20 and 21) includes projections extending radially inward fromthe inner diameter of the housing 710 and that slidably engage with thethreaded nuts 740 a, 740 b, 740 c, 740 d, 740 e, 740 f, 740 g, and 740h. Such projections mechanically restrain rotations of the threaded nuts740 a, 740 b, 740 c, 740 d, 740 e, 740 f, 740 g, and 740 h that mightotherwise result in response to rotations of the lead screws 730 a, 730b, 730 c, 730 d, 730 e, 730 f, 730 g, and 730 h.

Now, also referring to the schematic diagrams of FIGS. 9-14, theactuators 410, 420, and 430 correspond (in the context of the pod 700)to the combination of: (i) a motor, (ii) a corresponding drive gear,(iii) a corresponding driven gear, (iv) a corresponding leadscrew, and(v) a corresponding threaded nut. That is, in the depicted embodimentpod 700 includes eight actuators, each of which includes at least amotor, a leadscrew, and a threaded nut.

As described in reference to FIG. 14, in some embodiments the forcesexerted by individual actuators to the surgical instrument can bedetected by the use of one or more force detection devices. Theoutput(s) of such force detection devices can be used for controllingthe actuators, which in turn control movements of the surgicalinstrument and controls tensions of the tensioning members of thesurgical instrument.

In the depicted embodiment, load cells are used to detect thelongitudinal forces on the lead screws 730 a, 730 b, 730 c, 730 d, 730e, 730 f, 730 g, and 730 h. For example, a load cell, coupled to thedistal end plate 707, is located at the distal end of individual leadscrews 730 a, 730 b, 730 c, 730 d, 730 e, 730 f, 730 g, and 730 h. Thedistally-directed forces of the individual lead screws 730 a, 730 b, 730c, 730 d, 730 e, 730 f, 730 g, and 730 h can thereby be detected usingsuch load cells. When a surgical instrument is coupled with the pod 700,the distally-directed forces of the individual leadscrews 730 a, 730 b,730 c, 730 d, 730 e, 730 f, 730 g, and 730 h essentially equal thetensions of the corresponding tensioning members of the surgicalinstrument. Alternatively, or additionally, in some embodiments one ormore load cells can be coupled to the proximal end plate 705. Forexample, in some embodiments a load cell coupled to the proximal endplate 705 is used to detect the force associated with insertion of thesurgical instrument 600 (as described further below in reference toFIGS. 27-29). It will be recalled that as described above, the actuatorsmay actuate their component nuts in either the proximal or distaldirection, depending on instrument design, and so load cell placementtakes account of the actuation force direction applied to the instrumentfor tension or compression.

The use of load cells is not required in all embodiments. In someembodiments, other sensors and/or other devices can be used to detectthe forces exerted by the actuators to the surgical instrument. Forexample, in some embodiments strain gauges can be located on theactuator engagement members or elsewhere. In some embodiments, theelectrical current drawn by the electric motors of the actuators can bemeasured and used as an indication of the forces exerted by theactuators to the surgical instrument. In some embodiments, a combinationof such force detection devices and techniques can be used to enhancerobustness and redundancy of force sensing and the associated tension orcompression sensing for instrument control.

In some embodiments, devices and techniques are used to detect theposition of the actuators (e.g., the threaded nuts 740 a, 740 b, 740 c,740 d, 740 e, 740 f, 740 g, and 740 h and/or the motors 720 a, 720 b,720 c, 720 d, 720 e, 720 f, 720 g, and 720 h). For example, in thedepicted embodiment encoders are coupled to the distal end plate 707 andto individual ones of the motors 720 a, 720 b, 720 c, 720 d, 720 e, 720f, 720 g, and 720 h. Moreover, in some embodiments end-of-travel sensors(e.g., optical sensors, proximity sensors, and the like) for thethreaded nuts 740 a, 740 b, 740 c, 740 d, 740 e, 740 f, 740 g, and 740 hmay be included. In some embodiments, the end-of-travel positions of thethreaded nuts 740 a, 740 b, 740 c, 740 d, 740 e, 740 f, 740 g, and 740 hcan be detected by monitoring the current draw of the motors 720 a, 720b, 720 c, 720 d, 720 e, 720 f, 720 g, and 720 h (which increases whenthe threaded nuts 740 a, 740 b, 740 c, 740 d, 740 e, 740 f, 740 g, and740 h are at their end-of-travel limits).

FIG. 26 shows a partial longitudinal cross-section of the surgicalinstrument 600 coupled with the surgical instrument actuation pod 700and so depicts an exemplary arrangement for the engagement between athreaded nut of the pod 700 and an actuator engagement member of thesurgical instrument 600. In particular, in the depicted embodiment theactuator engagement member 634 a includes a laterally-extendingprojection that engages with a complementary receptacle defined by thethreaded nut 740 e. In this arrangement, proximally-directed forces fromthe threaded nut 740 e can be exerted against the actuator engagementmember 634 a (e.g., to tension the tensioning member that is coupled tothe actuator engagement member 634 a). However, since in this embodimentthe threaded nut 740 e is not fixed or latched to the actuatorengagement member 634 a (i.e., non-detained engagement),distally-directed forces cannot be exerted by the threaded nut 740 e tothe actuator engagement member 634 a. Therefore, the actuator engagementmember 634 a will readily uncouple from the threaded nut 740 e (e.g.,when the surgical instrument 600 is translated proximally in relation tothe pod 700 to uncouple the surgical instrument 600 from the pod 700).It will be recalled that in alternative embodiments, a portion of thethreaded nut extends laterally inward to engage the correspondingactuator engagement member in the instrument.

While not required in all embodiments, in the depicted embodiment theengagement between the threaded nut 740 a and the instrument shaftengagement member 620 is different than the engagement between the otherthreaded nuts and the other actuator engagement members. That is, in thedepicted embodiment the instrument shaft engagement member 620releasably latches to the threaded nut 740 a (i.e., detainedengagement). Therefore, both proximally-directed and distally-directedforces from the threaded nut 740 a can be exerted to the instrumentshaft engagement member 620 (e.g., to translationally insert and/orretract the surgical instrument 600 along the longitudinal axis 702 inrelation to the pod 700).

Referring to FIGS. 27-29, the surgical instrument 600 in a fully coupledarrangement with the surgical instrument actuation pod 700 is shown atthree different insertion depths. In FIG. 27, the surgical instrument600 is at a shallow (proximal-most) insertion depth in relation to thepod 700. In FIG. 28, the surgical instrument 600 is at an intermediateinsertion depth in relation to the pod 700. In FIG. 29, the surgicalinstrument 600 is at a deep (distal-most) insertion depth in relation tothe pod 700.

Changes of the insertion depth of the surgical instrument 600 can beactuated by movements of a linear actuator as described above,illustrated here in part as the threaded nut 740 a of the pod 700. Asthe threaded nut 740 a moves proximally and distally to adjust theinsertion depth of the surgical instrument 600, the other threaded nuts740 (here referred to jointly as the threaded nuts 740) and actuatorengagement members likewise move proximally and distally (by virtue ofactuations by the pod 700). If the pose of the end effector 650 remainsconstant as the insertion depth of the surgical instrument 600 isadjusted, the other threaded nuts 740 move proximally and distally bythe same distance as the distance moved by the threaded nut 740 a. Ifthe pose of the end effector 650 and the insertion depth of the surgicalinstrument 600 are simultaneously changed, although the average positionof the adjacent pairs of threaded nuts (and corresponding pairedactuator engagement members) moves proximally and distally by the samedistance as the distance moved by the threaded nut 740 a, the pairedthreaded nuts (and corresponding paired actuator engagement members)move differentially proximally and distally in relation to each other.Such differential movements of the paired threaded nuts (andcorresponding paired actuator engagement members) adjusts the pose ofthe end effector 650 along one or more degrees of freedom of the endeffector 650 as described above. Using the dynamic tension and positioncontrol concepts described herein, all such movements (i.e., changes tothe pose of the end effector 650 and/or changes to the insertion depthof the instrument 600 as a whole, which in turn changes the insertiondepth of the end effector) can be actuated while concurrentlycontrolling the tensions of the tensioning members of the surgicalinstrument 600 to a desired amount of tensile force.

In some embodiments, the assembly of the surgical instrument 600 coupledto the instrument drive system 700 (or pod 700) is rotated or rolledabout the longitudinal axes 702. It can be seen from FIGS. 21-29 thatthe plurality of motors, lead screws, and anti-rotation shafts arepositioned generally around the surgical instrument mounted in the pod.By positioning such components around the instrument (e.g., motors andlead screws equidistant from the longitudinal axis), the pod's inertiawith respect to its longitudinal axis is advantageously effectivelyindependent of its orientation around the pod's longitudinal axis.Accordingly, if the end effector roll orientation is changed by rollingthe pod around the longitudinal axis at the same time the end effectorposition is changed by pitching and/or yawing the longitudinal axis, thepitch and yaw control does not need to account for a change of inertiathat depends on pod roll orientation. Therefore, inventive aspectsinclude embodiments in which pod components are arranged to locate thecenter of mass of the pod along the pod's longitudinal axis—the axisaround which the pod rolls. In addition, inventive aspects includeembodiments in which pod components are advantageously located as closeas possible to the longitudinal axis, again to minimize inertia as themanipulator (see e.g., FIG. 19, manipulator assembly 800) changes thepod's orientation (e.g., changes pitch or yaw of the pod's longitudinalaxis). And as described above, the pod components are arranged to locatethe center of mass distally—in some instances as distally aspossible-along the pod's longitudinal axis in order to minimize theeffect of the pod's center of gravity on the manipulator's control ofthe pod's longitudinal axis orientation around the manipulator rollaxes.

While this specification contains many specific implementation details,these should not be construed as limitations on the scope of anyinvention or of what may be claimed, but rather as descriptions offeatures that may be specific to particular embodiments of particularinventions. Certain features that are described in this specification inthe context of separate embodiments can also be implemented incombination in a single embodiment. Conversely, various features thatare described in the context of a single embodiment can also beimplemented in multiple embodiments separately or in any suitablesubcombination. Moreover, although features may be described herein asacting in certain combinations and even initially claimed as such, oneor more features from a claimed combination can in some cases be excisedfrom the combination, and the claimed combination may be directed to asubcombination or variation of a subcombination.

Similarly, while operations are depicted in the drawings in a particularorder, this should not be understood as requiring that such operationsbe performed in the particular order shown or in sequential order, orthat all illustrated operations be performed, to achieve desirableresults. In certain circumstances, multitasking and parallel processingmay be advantageous. Moreover, the separation of various system modulesand components in the embodiments described herein should not beunderstood as requiring such separation in all embodiments, and itshould be understood that the described program components and systemscan generally be integrated together in a single product or packagedinto multiple products.

Particular embodiments of the subject matter have been described. Otherembodiments are within the scope of the following claims. For example,the actions recited in the claims can be performed in a different orderand still achieve desirable results. As one example, the processesdepicted in the accompanying figures do not necessarily require theparticular order shown, or sequential order, to achieve desirableresults. In certain implementations, multitasking and parallelprocessing may be advantageous.

We claim:
 1. A telesurgical system comprising: an actuation podcomprising: a proximal end, a distal end, a longitudinal axis definedbetween the proximal and distal ends of the actuation pod, a pluralityof linear actuators arranged concentrically around and extendingparallel to the longitudinal axis of the actuation pod; and a surgicalinstrument comprising: a shaft, and a plurality of actuator engagementmembers arranged radially around the instrument; wherein the shaft ofthe surgical instrument is positioned coincident with the longitudinalaxis of the actuation pod; and wherein each actuator engagement memberof the plurality of actuator engagement members is engaged with acorresponding linear actuator of the plurality of linear actuators withthe plurality of linear actuators being positioned radially around theplurality of actuator engagement members.
 2. The telesurgical system ofclaim 1, wherein the plurality of linear actuators comprises: aplurality of lead screws arranged around and extending parallel to thelongitudinal axis of the actuation pod; and a plurality of motors, eachmotor of the plurality of motors being coupled to drive a correspondinglead screw of the plurality of lead screws.
 3. The telesurgical systemof claim 2, wherein the plurality of motors are equidistant from thelongitudinal axis of the actuation pod.
 4. The telesurgical system ofclaim 2, wherein the plurality of motors are positioned distally in theactuation pod.
 5. The telesurgical system of claim 1, wherein theplurality of linear actuators comprises: a plurality of lead screwsarranged around and extending parallel to the longitudinal axis of theactuation pod; and a plurality of nuts, each nut of the plurality ofnuts being engaged with a corresponding lead screw of the plurality oflead screws, and each nut of the plurality of nuts being engaged with acorresponding actuator engagement member of the plurality of actuatorengagement members.
 6. The telesurgical system of claim 5, wherein theplurality of lead screws are equidistant from the longitudinal axis ofthe actuation pod.
 7. The telesurgical system of claim 5, wherein theplurality of lead screws extend from the distal end of the actuation podto the proximal end of the actuation pod.
 8. The telesurgical system ofclaim 1, wherein the plurality of linear actuators are equidistant fromthe longitudinal axis of the actuation pod.
 9. The telesurgical systemof claim 1, wherein the actuation pod further comprises a surgicalinstrument insertion linear actuator extending parallel to thelongitudinal axis of the actuation pod, wherein the surgical instrumentinsertion linear actuator is engaged with the surgical instrument. 10.The telesurgical system of claim 9, wherein the plurality of linearactuators and the surgical instrument insertion linear actuator areequidistant from the longitudinal axis of the actuation pod.
 11. Thetelesurgical system of claim 9, wherein the surgical instrumentinsertion linear actuator comprises: a surgical instrument insertionlead screw; a surgical instrument insertion motor coupled to drive thesurgical instrument insertion lead screw; and a surgical instrumentinsertion nut engaged with the surgical instrument insertion lead screw;wherein the surgical instrument insertion nut is engaged with thesurgical instrument.
 12. The telesurgical system of claim 9, wherein theplurality of linear actuators comprises: a plurality of lead screwsarranged around and extending parallel to the longitudinal axis of theactuation pod, and a plurality of motors, each motor of the plurality ofmotors being coupled to drive a corresponding lead screw of theplurality of lead screws; and wherein the surgical instrument insertionlinear actuator comprises: a surgical instrument insertion lead screw,and a surgical instrument insertion motor coupled to drive the surgicalinstrument insertion lead screw; and wherein the plurality of motors andthe surgical instrument insertion motor are equidistant from thelongitudinal axis of the actuation pod.
 13. The telesurgical system ofclaim 1, wherein the plurality of linear actuators comprises a pluralityof lead screws arranged around and extending parallel to thelongitudinal axis of the actuation pod; wherein the actuation podfurther comprises a surgical instrument insertion lead screw; andwherein the plurality of lead screws and the surgical instrumentinsertion lead screw are equidistant from the longitudinal axis of theactuation pod.
 14. The telesurgical system of claim 1, furthercomprising: a plurality of load sensors; wherein each load sensor of theplurality of load sensors is positioned at an end of a correspondinglinear actuator of the plurality of linear actuators.
 15. Thetelesurgical system of claim 1, further comprising: a plurality of loadsensors; wherein each load sensor of the plurality of load sensors ispositioned to sense an engagement force at a corresponding engagementbetween each of the linear actuators and each of the actuator engagementmembers.
 16. The telesurgical system of claim 1, wherein each actuatorengagement member of the plurality of actuator engagement members isengaged in a non-detained engagement with a corresponding linearactuator of the plurality of linear actuators.
 17. The telesurgicalsystem of claim 1, further comprising: a pod roll motor engaged to rollthe actuation pod around the longitudinal axis of the actuation pod. 18.The telesurgical system of claim 17, wherein the pod roll motor ispositioned inside the actuation pod.
 19. The telesurgical system ofclaim 1, further comprising: a manipulator assembly; wherein theactuation pod is mounted to the manipulator assembly; and wherein themanipulator assembly orients the longitudinal axis of the actuation podin pitch, yaw, or in both pitch and yaw.
 20. The telesurgical system ofclaim 19, wherein the actuation pod is mounted to the manipulatorassembly in a readily detachable way such that the actuation pod can beinterchanged with a second actuation pod.
 21. The telesurgical system ofclaim 1, wherein the plurality of linear actuators include a pluralityof motors arranged radially around the shaft of the surgical instrument.